Change search
Refine search result
2345678 201 - 250 of 2013
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 201.
    Boström, Tobias
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics. Fasta tillståndets fysik.
    Jensen, J
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Westin, Gunnar
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Wäckelgård, Ewa
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics. Fasta tillståndets fysik.
    Accelerated ageing tests of optimized solution chemically derived selective solar thermal absorbers2006Conference paper (Refereed)
  • 202.
    Boström, Tobias
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Valizadeh, Sima
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Westin, Gunnar
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Wäckelgård, Ewa
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    ERDA of Ni-Al2O3/SiO2 solar thermal selective absorbers2008In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 92, no 10, p. 1177-1182Article in journal (Refereed)
    Abstract [en]

    Thin film materials for the use in solar thermal absorbers have been investigated using time-of-flight energy elastic recoil detection analysis (ERDA). The ERDA measurements proved to be very efficient in detecting the elemental depth composition of a selective solar absorber. The three-layer absorber is composed of an 80% nickel-20% alumina film at the base, a 40% nickel-60% alumina layer in the middle and finally an AR film of silica or hybrid-silica film at the top. The difference between solution volume percent and actual volume percent could be investigated when studying individual nickel-alumina films with varying ratios coated on glass substrates. The result showed that there was a maximum difference of 3% between the calculated solution volume percent and the actual volume percentages in the solid films. The ERDA measurements also indicate that about 15% of the nickel found in the nickel-alumina composite films is bound in the form of NiO.

  • 203.
    Boström, Tobias
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Jensen, Jens
    jonfysik.
    Westin, Gunnar
    Wäckelgård, Ewa
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Accelerated ageing tests of optimized solution-chemically derived selective solar thermal absorbers2006In: Proceedings of Eurosun 2006Article in journal (Refereed)
  • 204.
    Boström, Tobias
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Solid State Physics. fasta tillståndets fysik.
    Westin, G
    Wäckelgård, Ewa
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Solid State Physics. fasta tillståndets fysik.
    Antireflection coatings for solution-chemically derived nickel-alumina solar absorbers2004In: Solar Energy Materials and Solar Cells, Vol. 84, p. 183-191Article in journal (Refereed)
  • 205.
    Boström, Tobias
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Westin, Gunnar
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Wäckelgård, Ewa
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Optimization of a solution-chemically derived solar absorbing spectrally selective surface2007In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 91, no 1, p. 38-43Article in journal (Refereed)
    Abstract [en]

    A previously studied solution chemically derived two layer absorber has been improved by adding a third layer. Simulations done with a thin film program showed that the optimized three layer selective absorber should be composed of an 80% nickel-20% alumina film of 100 nm at the base, a 40% nickel-60% alumina film of 60 nm in the middle and finally a 100% silica film of 85 nm at the top. Experimental results confirmed the computer simulated three layer structure. Prepared absorber consisting of the theoretically found optimized layer structure achieved a solar absorptance, alpha(sol), of 0.97 and a thermal emittance, epsilon(therm), of 0.05.

  • 206.
    Boström, Tobias
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Wäckelgård, Ewa
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Optical properties of solution-chemically derived thin film Ni-Al2O3 composites and Si, Al, and Si-Ti oxides2006In: Journal of Physics: Condensed Matter, ISSN 0953-8984, Vol. 18, p. 7737-7750Article in journal (Refereed)
  • 207.
    Boström, Tobias
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. Technology, Department of Engineering Sciences, Solid State Physics. Fasta tillståndets fysik.
    Wäckelgård, Ewa
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. Technology, Department of Engineering Sciences, Solid State Physics. Fasta tillståndets fysik.
    Westin, Gunnar
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. Technology, Department of Engineering Sciences, Solid State Physics. oorganisk kemi.
    Anti-reflection coatings for solution-chemically derived nickel—alumina solar absorbers2004In: Solar Energy Materials & Solar Cells, no 84, p. 183-191Article in journal (Refereed)
    Abstract [en]

    In order to suppress reflections from a solar absorber surface an anti-reflection (AR) layer is usually deposited on top of the solar absorbing coating. For the AR coating to function well it be made of a material with a lower refractive index than the underlying surface. Provided that the AR coating is sufficiently thin, it will not increase the thermal emittance value. Besides increasing the solar absorptance it is equally important that the AR layer is long term stable in order to create a successful solar selective coating. The objective was to create a highly efficient, flexible, inexpensive and durable AR coating for solar absorbers using simple techniques. Elastic properties are requested because it prohibits the formation of micro-cracks.

    Mumina, silica and hybrid silica AR coatings were synthesized using solution chemistry and )l-gel techniques. The AR coatings were deposited on the absorber surface using spin

    coating. The absorbers used without an AR layer had a normal solar absorptance of 0.79-0.81 and a normal thermal emittance of 0.03 The optimum anti-reflection coated sample acquired

    a normal solar absorptance of 0.93 while the thermal emittance remained unaltered. The study has shown that by adding a proper AR coating to a solar absorber the spectral selectivity can be considerably enhanced.

  • 208.
    Boström, Tobias
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. Technology, Department of Engineering Sciences, Solid State Physics. Fasta tillståndets fysik.
    Wäckelgård, Ewa
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. Technology, Department of Engineering Sciences, Solid State Physics. Fasta tillståndets fysik.
    Westin, Gunnar
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. Technology, Department of Engineering Sciences, Solid State Physics. oorganisk kemi.
    Solution-chemical derived nickel-alumina coatings for thermal solar absorbers2003In: Solar Energy, no 74, p. 497-503Article in journal (Refereed)
  • 209. Boulle, Olivier
    et al.
    Kimling, J.
    Warnicke, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Kläui, Mathias
    Malinowski, G.
    Swagten, H. J. M.
    Koopmans, B.
    Faini, G.
    Non-adiabatic spin transfer torque in high anisotropic magnetic nanowires with narrow domain walls2008In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 101, no 21, p. 1-4Article in journal (Refereed)
    Abstract [en]

    Current induced domain wall (DW) depinning of a narrow DW in out-of-plane magnetized (Pt/Co)3/Pt multilayer elements is studied by magnetotransport. We find that for conventional measurements Joule heating effects conceal the real spin torque efficiency and so we use a measurement scheme at a constant sample temperature to unambiguously extract the spin torque contribution. From the variation of the depinning magnetic field with the current pulse amplitude we directly deduce the large nonadiabaticity factor in this material and we find that its amplitude is consistent with a momentum transfer mechanism.

  • 210.
    Bovornratanaraks, Thiti
    et al.
    Chulalongkorn Univ, Fac Sci, Dept Phys, ECPRL, Bangkok, Thailand; Chulalongkorn Univ, Fac Sci, Dept Phys, PEMRU, Bangkok, Thailand; Commiss Higher Educ, Thailand Ctr Excellence Phys, Bangkok, Thailand.
    Tsuppayakorn-aek, Prutthipong
    Chulalongkorn Univ, Fac Sci, Dept Phys, ECPRL, Bangkok, Thailand; Chulalongkorn Univ, Fac Sci, Dept Phys, PEMRU, Bangkok, Thailand; Commiss Higher Educ, Thailand Ctr Excellence Phys, Bangkok, Thailand.
    Luo, Wei
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Ahuja, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory. Royal Inst Technol KTH, Appl Mat Phys, Dept Mat & Engn, Stockholm, Sweden.
    Ground-state structure of semiconducting and superconducting phases in xenon carbides at high pressure2019In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, article id 2459Article in journal (Refereed)
    Abstract [en]

    The 'missing Xe paradox' is one of the phenomena at the Earth's atmosphere. Studying the 'missing Xe paradox' will provide insights into a chemical reaction of Xe with C. We search the ground-state structure candidates of xenon carbides using the Universal Structure Predictor: Evolutionary Xtallography (USPEX) code, which has been successfully applied to a variety of systems. We predict that XeC2 is the most stable among the convex hull. We find that the I((4) over bar)2m structure of XeC2 is the semiconducting phase. Accurate electronic structures of tetragonal XeC2 have been calculated using a hybrid density functionals HSE06, which gives larger more accurate band gap than a GGA-PBE exchange-correlation functional. Specifically, we find that the I((4) over bar)2m structure of XeC2 is a dynamically stable structure at high pressure. We also predict that the P6/mmm structure of XeC2 is the superconducting phase with a critical temperature of 38 K at 200 GPa. The ground-state structure of xenon carbides is of critical importance for understanding in the missing Xe. We discuss the inference of the stable structures of XeC2. The accumulation of electrons between Xe and C led to the stability by investigating electron localization function (ELF).

  • 211.
    Boyadjiev, Stefan I.
    et al.
    “Georgi Nadjakov” Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko chaussee Blvd., 1784 Sofia, Bulgaria.
    Stefan, Nicolaie
    National Institute for Lasers, Plasma and Radiation Physics, 409 Atomistilor Street, RO-77125, Magurele-Ilfov, Romania.
    Stan, George
    National Institute of Materials Physics, 405A Atomistilor Street, Magurele-Ilfov, RO-077125, Romania.
    Arvizu, Miguel
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Szilágyi, Imre M.
    MTA-BME Technical Analytical Chemistry Research Group, Szent Gellért tér 4., H-1111, Budapest, Hungary and Budapest University of Technology and Economics, Department of Inorganic and Analytical Chemistry, 4 Műegyetem rakpart, H-1111, Budapest, Hungary.
    Visan, Anita
    National Institute for Lasers, Plasma and Radiation Physics, 409 Atomistilor Street, RO-77125, Magurele-Ilfov, Romania.
    Mihailescu, Natalia
    National Institute for Lasers, Plasma and Radiation Physics, 409 Atomistilor Street, RO-77125, Magurele-Ilfov, Romania.
    Mihailescu, Ion N.
    National Institute for Lasers, Plasma and Radiation Physics, 409 Atomistilor Street, RO-77125, Magurele-Ilfov, Romania.
    Besleaga, Cristina
    National Institute of Materials Physics, 405A Atomistilor Street, Magurele-Ilfov, RO-077125, Romania.
    Österlund, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Gesheva, Kostadinka A.
    Central Laboratory of Solar Energy and New Energy Sources, Bulgarian Academy of Sciences, 72 Tzarigradsko chaussee Blvd., 1784 Sofia, Bulgaria.
    Study of the electrochromic properties of MAPLE and PLD deposited WO3 thin films2017Conference paper (Refereed)
    Abstract [en]

    Tungsten trioxide (WO3) thin films were grown by matrix assisted pulsed laser evaporation (MAPLE) and pulsed laser deposition (PLD), and their properties were investigated for electrochromic applications. The structure, morphology and optical properties of these MAPLE and PLD grown from monoclinic WO3 nano-sized particles WO3 thin films were also studied. A KrF* excimer (λ=248 nm, ζFWHM=25 ns) laser source was used in all experiments. The films were studied by atomic force microscopy (AFM), grazing incidence X-ray diffraction (GIXRD) and Fourier transform infrared spectroscopy (FTIR). Cyclic voltammetry measurements were also performed in glove box with Ar atmosphere towards Li electrode, and the coloring and bleaching states were investigated. The morpho-structural investigations disclosed the synthesis of single-phase monoclinic WO3 films consisting of crystalline nano-grains embedded in an amorphous matrix. All thin films showed good electrochromic properties - strong coloration and fast and full bleaching. The effect was observed for many cycles, the strong coloration and full bleaching being preserved. These results are promising for future application of MAPLE and PLD deposited WO3 thin films in the development of electrochromic devices.

  • 212.
    Braesch-Andersen, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Magnetic fluids under applied field studied by light scattering and microscopy2017Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The optical response of several magnetic nanoparticle dispersions is studied by angle resolved transmittance at wavelength of 600 nm in zero-field and under an applied magnetic field of 0.1 T, with the purpose of exploring to what extent this could be used as a method of monitoring the colloidal dispersions. In an external magnetic field, magnetic particles will start to order into needle-like structures aligned with the field, which was observed by microscopy. This will change the light scattering caused by the particles. Results showed a clear effect from applying the magnetic field by a dip in the transmitted intensity at angles around 3-5 degrees. The scattering is compared to that of a homogeneous infinite cylinder and theoretical explanations to the effect are discussed. Spectrophotometry at wavelengths between 300-1100 nm is performed and compared with calculations from Kubelka-Munk approximation to give a first characterization of the particle dispersions. Particles used in this project are magnetite, Fe3O4, and maghemite, gamma-Fe2O3, nanoparticles with sizes ranging from 5-250 nm.

  • 213.
    Bran, Cristina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Hudl, Matthias
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Björck, Matts
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Kapaklis, Vassilios
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Andersson, Gabriella
    Magnetic Properties of Fe/WRe (001) multilayers2014In: Journal of Surfaces and Interfaces of Materials, Vol. 2, p. 33-Article in journal (Refereed)
    Abstract [en]

    Following recent theoretical predictions on perpendicular uniaxial magnetocrystalline anisotropy in multilayers of 5 monolayers of Fe and 2 monolayers of W x Re100–x with tetragonally strained components, we have measured the magnetization and detailed atomic structure in a series of such samples with x = 20–80 at%. Although the achieved strain in the WRe layers is smaller than in the modelled case, we do observe a positive uniaxial magnetocrystalline anisotropy of around 0.6 MJ/m3 at 40 K, after accounting for the in-plane shape anisotropy. This causes the out-of-plane saturation field to be reduced considerably compared to a pure Fe thin film, while the saturation magnetization is maintained at a value which is enhanced by at least 30% from what would be expected from the multilayer composition alone. The coercivity is low, on the order of 6 kA/m in all samples.

  • 214.
    Bright, Jamie M
    et al.
    Fenner School of Environment and Society, Australian National University, Canberra, Australia .
    Gueymard, Christian A
    Solar Consulting Services, Colebrook, NH, USA.
    Killinger, Sven
    Fraunhofer Institute for Solar Energy Systems ISE, 79100 Freiburg, Germany .
    Lingfors, David
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Sun, Xixi
    Department of Mathematics and System Sciences, Beihang University, Beijing, China .
    Wang, Peng
    Department of Mathematics and System Sciences, Beihang University, Beijing, China;Beijing Advanced Innovation Center for Big Data, Beihang University, Beijing, China .
    Engerer, Nicholas A
    Fenner School of Environment and Society, Australian National University, Canberra, Australia .
    Climatic and Global Validation of Daily MODIS Precipitable Water Data at AERONET Sites for Clear-sky Irradiance Modelling2018In: Proceedings of the ISES EuroSun 2018 Conference: 12th International Conference on Solar Energy for Buildings and Industry, International Solar Energy Society, 2018, p. 1490-1501Conference paper (Refereed)
    Abstract [en]

    Precipitable water (PW) is an influential variable in regards to clear-sky radiation modelling and solar resource assessment. Thus, the accuracy of solar energy estimates depends on the accuracy of PW measurements. Gridded satellite information is commonly used for solar modelling because of its benefit of a broad geographical coverage, thus a global validation of commonly utilised PW products is imperative. Here, all Level-3 Moderate Resolution Imaging Spectroradiometer (MODIS) daily PW products from the Aqua and Terra satellites (at 1° × 1° spatial resolution) from 01/2000 to 02/2018 are compared and validated against all of NASA’s ground-sensing Aerosol Robotic NETwork (AERONET) V3 Level-2 PW daily averages from sites that have at least one year of observa- tions during 2000–2018 (452 sites representing 675,158 observations). Furthermore, sub-categorisation by Kö- ppen-Geiger climate regions enables climate specific validation to ascertain any distinct climatic influence. The results demonstrate significant climatological influences that impact the derived PW products. It is found that the Terra PW is more accurate than the Aqua PW, and that blending these two products yields a higher accuracy of daily PW estimates. The MODIS PW product also suffers from overestimation at larger magnitudes (>3 cm). The absolute errors do not reduce linearly with the PW magnitude, so that relative errors are far worse in areas of low PW, such as the polar climate. The equatorial climate, with the highest PW records, behaves best. Finally, a simple sensitivity test using the REST2 clear-sky radiation model shows that the global PW RMSE (0.511 cm) of the combined MODIS data would result in a 1.5-2.5% under- or overestimate on direct normal irradiance (DNI) de- pending on latitude relative to using the AERONET mean PW of 1.8971 cm. It is thus concluded that the daily MODIS PW product is not ideal for clear-sky radiation modelling, at least whenever accurate DNI predictions are necessary on a global scale.

  • 215.
    Bright, Jamie M.
    et al.
    Australian Natl Univ, Fenner Sch Environm & Soc, Canberra, ACT 2601, Australia.
    Killinger, Sven
    Australian Natl Univ, Fenner Sch Environm & Soc, Canberra, ACT 2601, Australia.
    Lingfors, David
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics. Australian Natl Univ, Fenner Sch Environm & Soc, Canberra, ACT 2601, Australia.
    Engerer, Nicholas A.
    Australian Natl Univ, Fenner Sch Environm & Soc, Canberra, ACT 2601, Australia.
    Improved satellite-derived PV power nowcasting using real-time power data from reference PV systems2018In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 168, p. 118-139Article in journal (Refereed)
    Abstract [en]

    Rapid growth in the global penetration of solar photovoltaic (PV) systems means electricity network operators and electricity generators alike are increasingly concerned with the short-term solar forecasting (nowcasting) of solar irradiance. This paper proposes a methodology that considers a varying number of available reference PV systems for supporting satellite-derived PV power real-time nowcasting. We evaluate conventional satellite-only and upscaling-only PV fleet estimate methodologies and compare them to two newly developed correction and hybrid cases. When using only a single reference PV system to estimate the aggregated power of 48 independent target PV systems for the location of Canberra, Australia; we show that the newly proposed correction or hybrid cases improve the performance of the satellite-derived PV power estimate medians in terms of MBE, rMBE, RMSE and rRMSE from 0.031 W/W-p, 7.46%, 0.079 W/W-p and 23.4%, down to 0.006 W/W-p,-0.711%, 0.068 W/W-p and 20.0%, representing relative improvements of 80.6%, 90.5%, 13.9% and 14.5%, respectively. Similarly, when using 30 reference PV systems, we report median improvements from 0.036 W/W-p, 8.25%, 0.083 W/W-p and 24.8%, down to 0.01 W/W-p, 1.41%, 0.049 W/W-p and 11.4%, representing relative improvements of 72.2%, 82.9%, 41.0% and 54.0%, respectively. We discuss the fundamental challenges facing the use of reference PV systems, satellite-derived power estimates, combining the two data sources, and the knowledge required to address these issues. We ultimately conclude that combining satellite-based PV power estimates with data from reference PV systems is always more beneficial than either on their own.

  • 216.
    Bright, Jamie M
    et al.
    Australian National University.
    Killinger, Sven
    Fraunhofer ISE, Freiburg (Germany).
    Lingfors, David
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Engerer, Nicholas A
    Australian National University, Canberra (Australia).
    Integration of distributed solar forecasting with distribution network operations in Australia2017In: Proc. of the ISES Solar World Congress 2017, 2017Conference paper (Other academic)
    Abstract [en]

    Advances in solar integration technologies such as high-resolution solar forecasting and photovoltaic (PV) modelling are making it possible to remove some of the uncertainty facing electrical network operators and service providers with behind-the-meter (BtM) solar PV. However, a key challenge facing energy markets and networks is the integration ofthese technologies with their operations in a manner that is both useful and secure. The current lack of visibility of the aggregated power output from BtM solar PV within areas of the electrical distribution grid results in a dependency on reactive grid management; the future of effective management is to facilitate proactive strategies. Little published information is available on the usefulness ofsolar forecasting data at the distribution network level as well as best practice for the integration of such forecasts with their operations. This paper is intended to inform readers ofa large Australian Renewable Energy Agency (ARENA) fundedsolar forecasting research project at the Australian National University (ANU) in collaboration with new solar forecasting company Solcast. The overall aim is to offer distribution networks service providers (DNSPs) and other interested parties (e.g. researchers) with historic, real-time and forecasted BtM solar PV power outputs at multiple levels of the electricity grid infrastructure. To date, 11 of the 15 Australian DNSPs are partnered with the project and have started to use the solar forecasting information. Furthermore, at least one international inverter manufacturer has engaged in a partnership for real-time visibility of BtM solar PV systems. The first key take home message is that the project can deliver real-time solar estimates (currently at 30-min mean resolution) for anywhere around the world, along with a 7 day forecast; note that post-coded/substation specific information is only available where a DNSP has provided the relevant metadata. The second is that research collaborations are welcomed in order to work together to the overall goal of increasing the global penetration of solar PV in the world’s energy mix. The structure of this paper is as follows. The scene is set for BtM solar PV installations in Australia beforeintroducing the problems faced by DNSPs with regards to PV interaction with the electricity grid. A brief overview of the solar forecasting methodology is provided as well as the nature of the ARENA-funded ANU project collaboration with Solcast. The current status of the project is detailed before showing examples of the project in action. Lastly, the future outlook of the project is made stating the nature of contemporary and ambitious goals.

  • 217.
    Brogren, Maria
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Physics, Department of Physics and Materials Science, Materials Science. Department of Engineering Sciences, Solid State Physics. Fasta tillståndets fysik.
    Harding, GL
    Karmhag, Rikard
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Physics, Department of Physics and Materials Science, Materials Science. Department of Engineering Sciences, Solid State Physics. Fasta tillståndets fysik.
    Ribbing, C-G
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Physics, Department of Physics and Materials Science, Materials Science. Department of Engineering Sciences, Solid State Physics. Fasta tillståndets fysik.
    Niklasson, Gunnar
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Physics, Department of Physics and Materials Science, Materials Science. Department of Engineering Sciences, Solid State Physics. Fasta tillståndets fysik.
    Stenmark, Lars
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Physics, Department of Physics and Materials Science, Materials Science. Department of Engineering Sciences, Solid State Physics. ÅSTC.
    Titanium-aluminum-nitride coatings for satellite temperature control2000In: THIN SOLID FILMS, ISSN 0040-6090, Vol. 370, no 1-2, p. 268-277Article in journal (Refereed)
    Abstract [en]

    Intense solar irradiation, radiative cooling to outer space, and internal heat generation determine the equilibrium temperature of a spacecraft. The balance between the solar absorption and thermal emittance of the surface is therefore crucial, in particu

  • 218.
    Brogren, Maria
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Solid State Physics. Physics, Department of Physics and Materials Science, Materials Science. Fasta tillståndets fysik.
    Harding, G.L
    Karmhag, Rikard
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Solid State Physics. Physics, Department of Physics and Materials Science, Materials Science. Fasta tillståndets fysik.
    Ribbing, C-G
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Solid State Physics. Physics, Department of Physics and Materials Science, Materials Science. Fasta tillståndets fysik.
    Niklasson, Gunnar
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Solid State Physics. Physics, Department of Physics and Materials Science, Materials Science. Fasta tillståndets fysik.
    Stenmark, Lars
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Solid State Physics. Physics, Department of Physics and Materials Science, Materials Science. ÅSTC.
    TixAlyN coatings for temperature control of spacecraft1999In: Advances in Optical Interference Coatings, Berlin, 25-28 May, Proc SPIE 3738, 1999, p. 493-501Conference paper (Other scientific)
  • 219.
    Brogren, Maria
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Helgesson, Anna
    Karlsson, Björn
    Nilsson, Johan
    Roos, Arne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Optical properties, durability, and system aspects of a new aluminium-polymer-laminated steel reflector for solar concentrators2004In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 82, no 3, p. 387-412Article in journal (Refereed)
    Abstract [en]

    A newly developed aluminium-polymer-laminated steel reflector for use in solar concentrators was evaluated with respect to its optical properties, durability, and reflector performance in solar thermal and photovoltaic systems. The optical properties of the reflector material were investigated using spectrophotometer and scatterometry. The durability of the reflector was tested in a climatic test chamber as well as outdoors in Älvkarleby , Sweden. Before ageing, the solar weighted total and specular reflectance values were 82% and 77%, respectively, and the reflector scattered light isotropically. After 1 year's outdoor exposure, the total and specular solar reflectance had decreased by less than 1%. However, after in damp heat and simulated solar radiation, the optical properties had changed significantly: The light scattering was anisotropic and the total and specular solar reflectance values had decreased to 75% and 42%, respectively. The decrease was found to be due to degradation of the protective polyethylene terephthalate (PET) layer, caused by UV radiation and high temperature. The conclusions are that the degradation is climate dependent and that PET is not suitable as a protective coating under extreme conditions, such as those in the climatic test chamber. However, the results from outdoor testing indicate that the material withstands exposure in a normal Swedish climate.

  • 220.
    Brogren, Maria
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Solid State Physics. Fasta tillståndets fysik.
    Karlsson, B.
    Roos, Arne
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Solid State Physics. Fasta tillståndets fysik.
    Werner, Anna
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Solid State Physics. Fasta tillståndets fysik.
    Analysis of the effects of outdoor and accelerated aging on the optical properties of reflector materials for solar energy applications2004In: Solar Energy Materials and Solar Cells, no 82, p. 491-515Article in journal (Refereed)
  • 221.
    Brogren, Maria
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Solid State Physics. Physics, Department of Physics and Materials Science, Materials Science. Fasta tillståndets fysik.
    Larsson, Anna-Lena
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Solid State Physics. Physics, Department of Physics and Materials Science, Materials Science. Fasta tillståndets fysik.
    Harding, G.L
    Karmhag, Rikard
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Solid State Physics. Physics, Department of Physics and Materials Science, Materials Science. Fasta tillståndets fysik.
    Ribbing, C-G
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Solid State Physics. Physics, Department of Physics and Materials Science, Materials Science. Fasta tillståndets fysik.
    Niklasson, Gunnar
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Solid State Physics. Physics, Department of Physics and Materials Science, Materials Science. Fasta tillståndets fysik.
    Stenmark, Lars
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Solid State Physics. Physics, Department of Physics and Materials Science, Materials Science. ÅSTC.
    Optical coatings for temperature control of spacecraft1998In: Optik i Sverige, Stockholm, Sweden, 1998Conference paper (Refereed)
  • 222.
    Brogren, Maria
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electronics. Solid State Physics. Fasta tillståndets fysik.
    Wennerberg, Johan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electronics. Solid State Physics. Fasta tillståndets elektronik.
    Kapper, R
    Karlsson, B
    Design of concentrating elements with CIS thinfilm solar cells for façade integration. Solar Energy Materials & Solar Cells2003In: Solar Energy Materials & Solar Cells, Vol. 75, p. 567-575Article in journal (Refereed)
  • 223.
    Brohede, Ulrika
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Zhao, Shuxi
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Lindberg, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Mihranyan, Albert
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Forsgren, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    A novel graded bioactive high adhesion implant coating2009In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 255, no 17, p. 7723-7728Article in journal (Refereed)
    Abstract [en]

     One method to increase the clinical success rate of metal implants is to increase their bone bonding properties, i.e. to develop a bone   bioactive surface leading to reduced risks of interfacial problems.   Much research has been devoted to modifying the surface of metals to   make them become bioactive. Many of the proposed methods include   depositing a coating on the implant. However, there is a risk of coating failure due to low substrate adhesion. This paper describes a method to obtain bioactivity combined with a high coating adhesion via   a gradient structure of the coating. Gradient coatings were deposited   on Ti (grade 5) using reactive magnetron sputtering with increasing   oxygen content. To increase the grain size in the coating, all coatings   were post annealed at 385 degrees C. The obtained coating exhibited a gradual transition over 70 nm from crystalline titanium oxide (anatase)  at the surface to metallic Ti in the substrate, as shown using  cross-section transmission electron microscopy and X-ray photoelectron   spectroscopy depth pro. ling. Using scratch testing, it could be shown that the adhesion to the substrate was well above 1 GPa. The bioactivity of the coating was verified in vitro by the spontaneous   formation of hydroxylapatite upon storage in phosphate buffer solution at 37 degrees C for one week.   The described process can be applied to implants irrespective of bulk  metal in the base and should introduce the possibility to create safer permanent implants like reconstructive devices, dental, or spinal implants.

  • 224.
    Brucas, Rimantas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Hanson, M.
    Apell, P.
    Nordblad, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Gunnarsson, R.
    Hjörvarsson, Björgvin
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science.
    Tunneling and charging effects in discontinuous superparamagnetic Ni81Fe19/Al2O3 multilayers2010In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 81, no 22, p. 224437-Article in journal (Refereed)
    Abstract [en]

    The magnetic and transport properties of films based on discontinuous layers of Ni81Fe19 (Py) embedded in Al2O3 were investigated. In films with nominal Py thicknesses 6 and 8 angstrom superparamagnetic particles with median diameters D-med = 2.8 and 3.1 nm and distribution widths sigma(D)= 1.2 and 1.3 nm were formed. Current voltage (IU) curves were measured with the current perpendicular to the film plane. The analyses show that the charge transport occurs via tunneling; with the charging energy supplied by thermal fluctuations at high temperature, T >= 100 K, and by the electric field at low temperature, T < 10 K. The separation of the two regimes allows independent estimates of the mean charging energy < EC > approximate to 40 meV for both samples; from the resistance R versus T analyzed in an effective-medium model at high temperature and from I versus U at 4 K. In order to obtain a consistent description of the transport properties, the size distributions must be included to account for the deviation from the single size behavior R similar to exp(E-C/k(B)T) at high T. The scaling parameter in the relation I proportional to (U/U-th-1)(gamma), where U-th is the threshold for conduction, is estimated to gamma approximate to 2 at 4 K. The superparamagnetic relaxation of the particles becomes blocked below a temperature T approximate to 20 K respective 30 K for 6 and 8 angstrom. The magnetic field (B) dependence of the resistance R(B) displays a single maximum of the ratio MR = [R(B)-R(2 T)]/R(2 T) in zero field at room temperature and a characteristic splitting of the peak at 4 K, attributed to the blocking. The maxima, approximate to 0.9% for 6 angstrom and 1.1% for 8 angstrom, are positioned at fields about a factor of two to three higher than the coercive fields of the samples.

  • 225.
    Bručas, Rimantas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics. Chalmers tekniska högskola.
    Hanson, M.
    Chalmers tekniska högskola.
    Gunnarsson, R.
    Chalmers tekniska högskola.
    Wahlström, E.
    van Kampen, Maarten
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics.
    Hjörvarsson, Björgvin
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics.
    Lidbaum, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Experimental Physics.
    Leifer, Klaus
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Magnetic and transport properties of Ni81Fe19/Al2O3 granular multilayers approaching the superparamagnetic limit2007In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 101, no 7, p. 073907-Article in journal (Refereed)
    Abstract [en]

    The magnetic and transport properties of Ni81Fe 19/Al2O3 granular multilayer films were studied in relation to their structural properties as the nominal thickness t of the permalloy (Ni81Fe19) layer was varied near the percolation limit: in the range of 8≤t≤ 16 Å while keeping the nominal thickness of the Al2O3 layers constant at 16 Å. A good structural quality of the multilayers was demonstrated by low angle x-ray reflectivity measurements, and transmission electron microscopy showed the transition from continuous permalloy layers separated by aluminium oxide layers for t= 16 Å to metal grains dispersed in the insulator at t=8 Å. Magnetization measurements showed the gradual transition from ferromagnetic layers to superparamagnetic clusters and grains that successively become blocked as the temperature decreases. A strong correlation between transport and structural properties was observed in the temperature (T) dependence of the electrical resistance measured with the current in the plane in the range of 2 ≤T≤300 K: a gradual change of behavior from continuous permalloy layers with conducting interlayer connections for t=16 Å. to isolated permalloy grains in a dielectric for the film with t= 10 Å. The percolation occurs between 12 and 10 Å, as deduced both from the magnetic and resistive properties. The discontinuous metal films were analyzed within models for thermally assisted tunneling, yielding estimates of the tunneling barrier for intralayer conduction of about 20 meV for t= 10 Å. A significant magnetic field dependence of the resistance increasing with decreasing temperature was observed in all samples.

  • 226. Buchanan, K S
    et al.
    Roy, P E
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Solid State Physics. Fasta tillståndets fysik.
    Grimsditch, M
    Fradin, F Y
    Guslienko, K Yu
    Bader, S D
    Novosad, V
    Soliton-pair dynamics in patterned ferromagnetic ellipses2005In: Nature Physics, Vol. 1, p. 172-176Article in journal (Refereed)
  • 227. Buchanan, K S
    et al.
    Roy, Pierre E
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics. Fasta tillståndets fysik.
    Grimditch, M
    Frandin, F Y
    Guslienko, K Yu
    Bader, S D
    Novosad, V
    Soliton-pair dynamics in patterned ferromagnetic ellipses2006In: Nature Physics, Vol. 1, no 3, p. 172-6Article in journal (Refereed)
  • 228. Buchanan, Kristen S.
    et al.
    Roy, Pierre E.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Fradin, Frank Y.
    Guslienko, Konstantin
    Grimsditch, Marcos
    Bader, Sam D.
    Novosad, Val
    Vortex dynamics in patterned ferromagnetic ellipses2006In: Journal of Applied Physics, ISSN 0021-8979, Vol. 99, p. 08C707-Article in journal (Refereed)
  • 229. Buchanan, Kristen S
    et al.
    Roy, Pierre E
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics. Fasta tillståndets fysik.
    Fradin, Frank Y
    Guslienko, Konstatin Yu
    Grimsditch, Marcos
    Bader, Sam D
    Novosad, Val
    Vortex dynamics in patterned ferromagnetic ellipses2006In: Journal of Applied Physics, no n 8, p. p 8C707-1Article in journal (Refereed)
  • 230. Buchanan, Kristen S.
    et al.
    Roy, Pierre E.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Grimsditch, Marcos
    Fradin, Frank Y.
    Guslienko, Konstantin
    Bader, Sam D.
    Novosad, Val
    Magnetic-field tunability of the vortex translational mode in micron-sized permalloy ellipses: Experiment and micromagnetic modeling2006In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 74, no 6, p. 064404-Article in journal (Refereed)
    Abstract [en]

    A magnetic vortex confined in a magnetically soft ferromagnet with micron-sized dimensions possesses a characteristic dynamic excitation known as a translational mode that corresponds to spiral-like precession of the vortex core around its equilibrium position. We report micromagnetic modeling and experimental detection using a microwave reflection technique of the magnetic field tunability of this mode in 40 nm thick, 3x1.5 mu m(2) and 2x1 mu m(2) permalloy ellipses. At remanence the translational modes are detected at 77 and 118 MHz. The frequency shows a strongly anisotropic dependence on magnetic field applied in the plane of the ellipse. The frequencies more than double when a static field is applied along the hard (short) axis, whereas they are almost field-independent when the field is aligned with the easy (long) axis. Micromagnetic calculations reveal that the observed behavior is governed by the shape of the energy potential well that is influenced mainly by magnetostatic and Zeeman energies.

  • 231. Buchanan, Kristen S.
    et al.
    Roy, Pierre E.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Grimsditch, Marcos
    Fradin, Frank Y.
    Guslienko, Konstantin
    Bader, Sam D.
    Novosad, Valentyn
    Soliton-pair dynamics in patterned ferromagnetic ellipses2005In: Nature Physics, ISSN 1745-2473, Vol. 1, no 3, p. 172-176Article in journal (Refereed)
  • 232.
    Burkert, Till
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics.
    Svedlindh, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Andersson, Gabriella
    Hjörvarsson, Björgvin
    Magnetic ordering in a weakly coupled Fe/V(001) superlattice2002In: Physical Review B, ISSN 0163-1829, Vol. 66, no 22, p. 220402(R)-Article in journal (Refereed)
    Abstract [en]

    A large shift of the ordering temperature is observed in an Fe3/V13(001) superlattice upon altering the interlayer coupling J′. The modification of J′ is accomplished by temporary alloying of the V spacer layers with hydrogen. A phase with short-range magnetic order is found in a wide temperature range between the paramagnetic phase and the onset of long-range order. It is interpreted as two-dimensional-XY behavior and is attributed to the absence of an in-plane magnetic anisotropy and the vanishing of the interlayer exchange coupling close to the ordering temperature.

  • 233. Burks, T
    et al.
    Avila, M
    Akhtar, F
    Gothelid, M
    Lansåker, Pia C
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Toprak, M S
    Muhammed, M
    Uheida, A
    Studies on the adsorption of chromium(VI) onto 3-Mercaptopropionic acid coated superparamagnetic iron oxide nanoparticles2014In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 425, p. 36-43Article in journal (Refereed)
    Abstract [en]

    Chromium (Cr) in the form of Cr(VI) is deemed toxic in water due to its mutagenic and carcinogenic properties. For the successful removal of Cr(VI), we demonstrate a novel adsorbent consisting of superparamagnetic iron oxide nanoparticles (SPION) functionalized with 3-Mercaptopropionic acid (3-MPA). Fourier transform infrared spectroscopy (FT-IR) confirmed the functionalization of nanoparticles and presence of sulfonate groups. Batch adsorption experiments showed that the functionalized adsorbent recovered 45 mg of Cr(VI)/g of 3-MPA coated SPION at initial concentration of 50 mg/L aqueous solution at pH 1 with less than 1% of Fe dissolution from SPION. The results from X-ray photoelectron spectroscopy confirmed that Cr(VI) chemisorbed onto the adsorbent. Hence, the XPS spectra did not indicate any reduction of Cr(VI) to Cr(III) upon adsorption. The adsorption data were better fitted for the Freundlich model. Moreover, the Cr(VI) adsorption kinetics on functionalized SPION followed a pseudo-second order rate, revealing chemisorption as the dominant mechanism. The high Cr(VI) removal, rapid adsorption kinetics and stability of adsorbent indicate that 3-MPA coated SPION could be an efficient adsorbent for the removal of Cr(VI). (C) 2014 Elsevier Inc. All rights reserved.

  • 234. Buyan, M
    et al.
    Beuhwiler, P A
    Azens, Andris
    Gustavsson, Greger
    Karmhag, Richard
    Granqvist, Claes G
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics. Fasta tillståndets fysik.
    Facial Warming with Tinted Helmet Visors2006In: Int. J. Ind. Ergon., no 36, p. 11-16Article in journal (Refereed)
  • 235.
    Böhnke, Tobias
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Division for Electricity and Lightning Research.
    Kratz, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    Hultåker, Annette
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Köhler, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Division for Electricity and Lightning Research.
    Edoff, Marika
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Roos, Arne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Ribbing, Carl-Gustaf
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    Surfaces with high solar reflectance and high thermal emittance on structured silicon for spacecraft thermal control2008In: Optical materials (Amsterdam), ISSN 0925-3467, E-ISSN 1873-1252, Vol. 30, no 9, p. 1410-1421Article in journal (Refereed)
    Abstract [en]

    Presented here is an examination of unstructured and structured (by anisotropic etching), monocrystalline silicon wafers coated with sputter deposited aluminum and chemical vapor deposited silicon dioxide for high solar reflectance and high thermal emittance, respectively. The topography of the samples was characterized with optical and scanning electron microscopy. Optical properties were examined with reflectance and transmittance spectroscopy, partly by usage of an integrating sphere. The measurement results were used to estimate the equilibrium temperature of the surfaces in space. The suitability of the surfaces with high solar reflectance and high thermal emittance to aid in the thermal control of miniaturized, highly integrated components for space applications is discussed. A silicon dioxide layer on a metal layer results in a slightly lower reflectance when compared to surfaces with only a metal layer, but might be beneficial for miniaturized space components and modules that have to dissipate internally generated heat into open space. Additionally, it is an advantage to microstructure the emitting surface for enhanced radiation of excess heat.

  • 236.
    Cai, Yixao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Almandoz-Gil, Leire
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Public Health and Caring Sciences, Geriatrics.
    Karlsson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Nikolajeff, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Österund, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Bergström, Joakim
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Public Health and Caring Sciences, Geriatrics.
    ATR- FTIR spectroscopy study of oxidative modification of the a-synuclein secondary structure2013Conference paper (Refereed)
  • 237.
    Cai, Yixiao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Lendel, Christofer
    Österlund, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Kasrayan, Alex
    Lannfelt, Lars
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Public Health and Caring Sciences, Geriatrics.
    Ingelsson, Martin
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Public Health and Caring Sciences, Geriatrics.
    Nikolajeff, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Karlsson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Bergström, Joakim
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Public Health and Caring Sciences, Geriatrics.
    Changes in secondary structure of α-synuclein during oligomerization induced by reactive aldehydes.2015In: Biochemical and Biophysical Research Communications - BBRC, ISSN 0006-291X, E-ISSN 1090-2104, Vol. 464, no 1, p. 336-341Article in journal (Refereed)
    Abstract [en]

    The oxidative stress-related reactive aldehydes 4-hydroxy-2-nonenal (HNE) and 4-oxo-2-nonenal (ONE) have been shown to promote formation of α-synuclein oligomers in vitro. However, the changes in secondary structure of α-synuclein and the kinetics of the oligomerization process are not known and were the focus of this study. Size exclusion chromatography showed that after 1 h of incubation, HNE induced the formation of an oligomeric α-synuclein peak with a molecular weight of about ∼2000 kDa, which coincided with a decreasing ∼50 kDa monomeric peak. With prolonged incubation (up to 24 h) the oligomeric peak became the dominating molecular species. In contrast, in the presence of ONE, a ∼2000 oligomeric peak was exclusively observed after 15 min of incubation and this peak remained constant with prolonged incubation. Western blot analysis of HNE-induced α-synuclein oligomers showed the presence of monomers (15 kDa), SDS-resistant low molecular (30-160 kDa) and high molecular weight oligomers (≥260 kDa), indicating that the oligomers consisted of both covalent and non-covalent protein. In contrast, ONE-induced α-synuclein oligomers only migrated as covalent cross-linked high molecular-weight material (≥300 kDa). Both circular dichroism (CD) and Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy showed that the formation of HNE- and ONE-induced oligomers coincided with a spectral change from random coil to β-sheet. However, ONE-induced α-synuclein oligomers exhibited a slightly higher degree of β-sheet. Taken together, our results indicate that both HNE and ONE induce a change from random coil to β-sheet structure that coincides with the formation of α-synuclein oligomers. Albeit through different kinetic pathways depending on the degree of cross-linking.

  • 238. Candanedo, José
    et al.
    Salom, Jaume
    Widén, Joakim
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Athienitis, Andreas
    Load matching, grid interaction, and advanced control2015In: Modeling, Design, and Optimization of Net-Zero Energy Buildings / [ed] Athienitis, Andreas; O'Brien, William, John Wiley & Sons, 2015Chapter in book (Refereed)
  • 239.
    Cappel, Ute B.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Plogmaker, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Terschlüsen, Joachim A.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Leitner, Torsten
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics. Uppsala Berlin Joint Lab Next Generat Photoelectr, Albert Einstein Str 15, D-12489 Berlin, Germany..
    Johansson, Erik M. J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Edvinsson, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Sandell, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Karis, Olof
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Siegbahn, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Svensson, Svante
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics. Uppsala Berlin Joint Lab Next Generat Photoelectr, Albert Einstein Str 15, D-12489 Berlin, Germany..
    Mårtensson, Nils
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics. Uppsala Berlin Joint Lab Next Generat Photoelectr, Albert Einstein Str 15, D-12489 Berlin, Germany..
    Rensmo, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Söderström, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Electronic structure dynamics in a low bandgap polymer studied by time-resolved photoelectron spectroscopy2016In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 18, no 31, p. 21921-21929Article in journal (Refereed)
    Abstract [en]

    Means to measure the temporal evolution following a photo-excitation in conjugated polymers are a key for the understanding and optimization of their function in applications such as organic solar cells. In this paper we study the electronic structure dynamics by direct pump-probe measurements of the excited electrons in such materials. Specifically, we carried out a time-resolved photoelectron spectroscopy (TRPES) study of the polymer PCPDTBT by combining an extreme ultraviolet (XUV) high harmonic generation source with a time-of-flight spectrometer. After excitation to either the 1st excited state or to a higher excited state, we follow how the electronic structure develops and relaxes on the electron binding energy scale. Specifically, we follow a less than 50 fs relaxation of the higher exited state and a 10 times slower relaxation of the 1st excited state. We corroborate the results using DFT calculations. Our study demonstrates the power of TRPES for studying photo-excited electron energetics and dynamics of solar cell materials.

  • 240.
    Cappel, Ute B.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Plogmaker, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Terschlüsen, Joachim Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Leitner, Thorsten
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Johansson, Erik J. M.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Edvinsson, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Sandell, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Karis, Olof
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Siegbahn, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Svensson, Svante
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Mårtensson, Nils
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Rensmo, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Söderström, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Direct measurement of excited electrons in a low bandgap polymer using XUV based time-resolved photoelectron spectroscopyIn: Article in journal (Refereed)
  • 241.
    Cardias, Ramon
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Bezerra-Neto, M. M.
    Instituto de Engenharia e Geociências, Universidade Federal do Oeste do Pará, Santarém, PA, Brazil.
    Ribeiro, M. S.
    Instituto Federal do Pará, Campus Belém, PA, Brazil.
    Szilva, Attila
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Bergman, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Nordström, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Kvashnin, Yaroslav
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Fransson, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
    Klautau, A. B.
    Faculdade de Física, Universidade Federal do Pará, Belém, Pará, Brazil.
    Eriksson, Olle
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
    First-principles Dzyaloshinskii-Moryia interaction in a non-collinear frameworkManuscript (preprint) (Other academic)
    Abstract [en]

    Including dierent terms in the spin-Hamiltonian, we have derived an expression for theDzyaloshinskii-Moryia vector interaction (DMI) where all the three components of the vector canbe calculated independently of the magnetic conguration. Here, we have chosen the Cr triangulartrimer on Au(111) and Mn triangular trimes on Ag(111) and Au(111) surfaces to study the implementationof the derived DMI into the RS-LMTO-ASA method. Our results have shown thatthe DMI value (module and direction) is drastically dierent for collinear and non-collinear states.Based on relation between the spin and charge currents owing in the system and the non-collinearmagnetic conguration of the triangular trimer, we argued that the drastic change between the DMIcalculated considering a collinear and a non-collinear magnetic conguration can be explained bythe mechanism behind the spin and charge currents owing through the atoms when the spins arealigned in a non-collinear fashion.

  • 242. Carlegrim, Elin
    et al.
    Kanciurzewska, Anna
    Nordblad, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Fahlman, Mats
    Air-stable organic-based semiconducting room temperature thin film magnet for spintronics applications2008In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 92, no 16, p. 163308-Article in journal (Refereed)
    Abstract [en]

    Herein, we report on a preparation method of vanadium tetracyanoethylene, V(TCNE)(x), an organic-based semiconducting room temperature thin film magnet. Previously, this compound has been reported to be extremely air sensitive but this preparation method leads to V(TCNE)(x), which can retain its magnetic ordering at least several weeks in air. The electronic structure has been studied by photoelectron spectroscopy and the magnetic properties by superconducting quantum interference device. The properties mentioned above, in combination with complete spin polarization, makes this air-stable V(TCNE)(x) a very promising material for spintronic devices.

  • 243.
    Carlsson, P A
    et al.
    Chalmers University of Technology.
    Österlund, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Thormahlen, P
    Chalmers University of Technology.
    Palmqvist, A E C
    Chalmers University of Technology.
    Fridell, E
    Chalmers University of Technology.
    Jansson, J
    Chalmers University of Technology.
    Skoglundh, M
    Chalmers University of Technology.
    A transient in situ FTIR and XANES study of CO oxidation over Pt/Al2O3 catalysts2004In: Journal of Catalysis, ISSN 0021-9517, E-ISSN 1090-2694, Vol. 226, no 2, p. 422-434Article in journal (Refereed)
    Abstract [en]

    We report experimental results for the oxidation of CO over supported Pt/Al2O3 catalysts operating in oxygen excess at atmospheric pressure. To study the reaction kinetics under transient conditions we have employed step changes of the O-2 concentration by intermittently switching off the O-2 supply at various temperatures ranging from 523 to 623 K. Detailed in situ FTIR and XANES data for CO coverage and the chemical state of Pt, respectively, are presented together with the CO conversion, which in both cases was monitored by mass spectrometry. A red-shift of the vibrational frequency of linearly bonded CO which correlates with a blue-shift of the Pt L-III binding energy indicates that the Pt catalyst initially is partially oxidised and gradually reduced when the O-2 supply is switched off. Control experiments with a NO2 oxidised Pt/Al2O3 catalyst support these findings. A hysteresis in the catalytic activity due to the different rates whereby Pt is oxidised and reduced as a function of gas-phase composition is observed. The activation energy for the Pt oxide reduction (decomposition) process is estimated to be about 50 kJ/mol. The results further emphasise that the conventional three-step Langmuir-Hinshelwood (LH) scheme used to interpret CO oxidation on Pt surfaces must be complemented by a Pt oxidation and reduction mechanism during transient conditions. Moreover, FTIR data suggest that during the extinction, the partially oxidised platinum surface is reduced by chemisorbed CO which should be explicitly accounted for in the modeling of the reaction mechanism. (C) 2004 Elsevier Inc. All rights reserved.

  • 244.
    Caron, L.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Hudl, M.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Höglin, Viktor
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Dung, N. H.
    Gómez, Cesar Pay
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Sahlberg, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Bruck, E.
    Andersson, Yvonne
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Nordblad, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Magnetocrystalline anisotropy and the magnetocaloric effect in Fe2P2013In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 88, no 9, p. 094440-Article in journal (Refereed)
    Abstract [en]

    Magnetic and magnetocaloric properties of high-purity, giant magnetocaloric polycrystalline and single-crystalline Fe2P are investigated. Fe2P displays a moderate magnetic entropy change, which spans over 70 K and the presence of strong magnetization anisotropy proves this system is not fully itinerant but displays a mix of itinerant and localized magnetism. The properties of pure Fe2P are compared to those of giant magnetocaloric (Fe,Mn)2(P,A) (where A = As, Ge, Si) compounds helping understand the exceptional characteristics shown by the latter, which are so promising for heat pump and energy conversion applications.

  • 245.
    Caron, Luana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Trung, N T
    Fundamental Aspects of Materials and Energy, Faculty of Applied Sciences, TU Delft, Nederländerna.
    Brück, E
    Fundamental Aspects of Materials and Energy, Faculty of Applied Sciences, TU Delft, Nederländerna.
    Pressure-tuned magnetocaloric effect in Mn(0.93)Cr(0.07)CoGe2011In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 84, no 2, p. 020414-Article in journal (Refereed)
    Abstract [en]

    Effects of physical and chemical pressures in the Mn(1-x)Cr(x)CoGe series of compounds are studied. Cr substitution and hydrostatic pressure play similar roles in displacing T(C) to lower temperatures and coupling or decoupling magnetic and crystallographic transitions. In this work the similarities and differences between the effects of chemical and physical pressures are explored, helping unveil the nature of the first-order phase transition presented by MnCoGe-based compounds.

  • 246.
    Cedervall, Johan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Andersson, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Chalmers Univ Technol, Dept Chem & Chem Engn, SE-41296 Gothenburg, Sweden.
    Delczeg-Czirjak, Erna Krisztina
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Iusan, Diana
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Pereiro, Manuel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Roy, P.
    Radboud Univ Nijmegen, Inst Mol & Mat, Heyendaalseweg 135, NL-6525 AJ Nijmegen, Netherlands.
    Ericsson, Tore
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
    Häggström, Lennart
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
    Lohstroh, W.
    Tech Univ Munich, Heinz Maier Leibnitz Zentrum MLZ, Garching Bei Munchen, Lichtenbergstr, D-185748 Garching, Germany.
    Mutka, H.
    Inst Laue Langevin, BP 156, F-38042 Grenoble 9, France.
    Sahlberg, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Nordblad, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Deen, P. P.
    European Spallat Source ESS ERIC, Box 176, SE-22100 Lund, Sweden;Univ Copenhagen, Nanosci Ctr, Niels Bohr Inst, DK-2100 Copenhagen O, Denmark.
    Magnetocaloric effect in Fe2P: Magnetic and phonon degrees of freedom2019In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 99, no 17, article id 174437Article in journal (Refereed)
    Abstract [en]

    Devices based on magnetocaloric materials provide great hope for environmentally friendly and energy efficient cooling that does not rely on the use of harmful gasses. Fe2P based compounds are alloys that have shown great potential for magnetocaloric devices. The magnetic behavior in Fe2P is characterized by a strong magnetocaloric effect that coexists with a first-order magnetic transition (FOMT). Neutron diffraction and inelastic scattering, Mossbauer spectroscopy, and first-principles calculations have been used to determine the structural and magnetic state of Fe2P around the FOMT. The results reveal that ferromagnetic moments in the ordered phase are perturbed at the FOMT such that the moments cant away from the principle direction within a small temperature region. The acoustic-phonon modes reveal a temperature-dependent nonzero energy gap in the magnetically ordered phase that falls to zero at the FOMT. The interplay between the FOMT and the phonon energy gap indicates hybridization between magnetic modes strongly affected by spin-orbit coupling and phonon modes leading to magnon-phonon quasiparticles that drive the magnetocaloric effect.

  • 247.
    Cedervall, Johan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Andersson, Mikael Svante
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Industrial Engineering & Management.
    Iusan, Diana
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Delczeg-Czirjak, Erna Krisztina
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Nordblad, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Sahlberg, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Magnetic and mechanical effects of Mn substitutions in AlFe2B22019In: Journal of Magnetism and Magnetic Materials, ISSN 0304-8853, E-ISSN 1873-4766, Vol. 482, p. 54-60Article in journal (Refereed)
    Abstract [en]

    The mechanical and magnetic properties of the newly discovered MAB-phase class of materials based upon AlFe2B2 were investigated. The samples were synthesised from stoichiometric amounts of all constituent elements. X-ray diffraction shows that the main phase is orthorhombic with an elongated b-axis, similar to AlFe2B2. The low hardness and visual inspection of the samples after deformation indicate that these compounds are deformed via a delamination process. When substituting iron in AlFe2B2 with manganese, the magnetism in the system goes from being ferro- to antiferromagnetic via a disordered ferrimagnetic phase exhibited by AlFeMnB2. Density functional theory calculations indicate a weakening of the magnetic interactions among the transitions metal ions as iron is substituted by manganese in AlFe2B2. The Mn-Mn exchange interactions in AlMn2B2 are found to be very small.

  • 248.
    Cedervall, Johan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Andersson, Mikael Svante
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Sarkar, Tapati
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Delczeg-Czirjak, Erna K.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Bergqvist, Lars
    Hansen, Thomas C.
    Beran, Premysl
    Nordblad, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Sahlberg, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Magnetic structure of the magnetocaloric compound AlFe2B22016In: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 654, p. 784-791Article in journal (Refereed)
    Abstract [en]

    The crystal and magnetic structures of AlFe2B2 have been studied with a combination of X-ray and neutron diffraction and electronic structure calculations. The magnetic and magnetocaloric properties have been investigated by magnetisation measurements. The samples have been produced using high temperature synthesis and subsequent heat treatments. The compound crystallises in the orthorhombic crystal system Cmmm and it orders ferromagnetically at 285 K through a second order phase transition. At temperatures below the magnetic transition the magnetic moments align along the crystallographic a-axis. The magnetic entropy change from 0 to 800 kA/m was found to be - 1.3 J/K kg at the magnetic transition temperature.

  • 249.
    Cedervall, Johan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Beran, Premysl
    ASCR, Inst Nucl Phys, Hlavni 130, Rez 25068, Czech Republic.
    Vennström, Marie
    AB Sandvik Mat Technol, SE-81181 Sandviken, Sweden.
    Danielsson, Therese
    Etteplan Sweden AB, SE-17154 Solna, Sweden.
    Ronneteg, Sabina
    AB Sandvik Mat Technol, SE-81181 Sandviken, Sweden.
    Höglin, Viktor
    Scienta Sauna Syst AB, SE-75228 Uppsala, Sweden.
    Lindell, David
    Swerea KIMAB AB, Box 7047, SE-16407 Kista, Sweden.
    Eriksson, Olle
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    André, Gilles
    CEA Saclay, LLB, F-91191 Gif Sur Yvette, France.
    Andersson, Yvonne
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Nordblad, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Sahlberg, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Low temperature magneto-structural transitions in Mn3Ni20P62016In: Journal of Solid State Chemistry, ISSN 0022-4596, E-ISSN 1095-726X, Vol. 237, p. 343-348Article in journal (Refereed)
    Abstract [en]

    Abstract X-ray and neutron powder diffraction has been used to determine the crystal and magnetic structure of Mn3Ni20P6. The crystal structure can be described as cubic with space group Fm 3 ¯ m (225) without any nuclear phase transformation within studied temperature interval from room temperature down to 4 K. The magnetic structure of Mn3Ni20P6 is complex with two independent magnetic positions for the Mn atoms and the compound passes three successive magnetic phase transitions during cooling. At 30 K the spins of the Mn atoms on the Wyckoff 4a site (Mn1) order to form a primitive cubic antiferromagnetic structure with propagation vector k=(0 0 1). Between 29 and 26 K the Mn atoms on the Wyckoff 8c site (Mn2) order independently on already ordered Mn1 magnetic structure forming a commensurate antiferromagnetic structure with propagation vector k=(0 0 ½) and below 26 K, both Mn positions order to form an incommensurate helical structure with propagation vector k=(0 0 ~0.45). Magnetization vs. temperature curve of Mn3Ni20P6 shows a steep increase indicating some magnetic ordering below 230 K and a sharp field dependent anomaly in a narrow temperature range around 30 K.

  • 250.
    Cedervall, Johan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Kontos, Sofia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Hansen, Thomas C.
    Balmes, Olivier
    Martinez-Casado, Francisco Javier
    Matej, Zdenek
    Beran, Premysl
    Svedlindh, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Gunnarsson, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Sahlberg, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Magnetostructural transition in Fe5SiB2 observed with neutron diffraction2016In: Journal of Solid State Chemistry, ISSN 0022-4596, E-ISSN 1095-726X, Vol. 235, p. 113-118Article in journal (Refereed)
    Abstract [en]

    The crystal and magnetic structure of Fe5SiB2 has been studied by a combination of X-ray and neutron diffraction. Also, the magnetocrystalline anisotropy energy constant has been estimated from magnetisation measurements. High quality samples have been prepared using high temperature synthesis and subsequent heat treatment protocols. The crystal structure is tetragonal within the space group I4/mcm and the compound behaves ferromagnetically with a Curie temperature of 760 K. At 172 K a spin reorientation occurs in the compound and the magnetic moments go from aligning along the c-axis (high T) down to the ab-plane (low T). The magnetocrystalline anisotropy energy constant has been estimated to 03 MJ/m(3) at 300 K.

2345678 201 - 250 of 2013
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf