Change search
CiteExportLink to record
Permanent link

Direct 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
Hysteresis-free switching between vortex and collinear magnetic states
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
Show others and affiliations
2014 (English)In: New Journal of Physics, ISSN 1367-2630, E-ISSN 1367-2630, Vol. 16, p. 053002-Article in journal (Refereed) Published
Abstract [en]

We demonstrate a lossless switching between vortex and collinear magnetic states in circular FePd disks arranged in a square lattice. Above a bifurcation temperature (Te) we show that thermal fluctuations are enough to facilitate flipping between the two distinctly different magnetic states. We find that the temperature dependence of the vortex annihilation and nucleation fields can be described by a simple power law relating them to the saturation magnetization.

Place, publisher, year, edition, pages
2014. Vol. 16, p. 053002-
National Category
Condensed Matter Physics
Identifiers
URN: urn:nbn:se:uu:diva-224245DOI: 10.1088/1367-2630/16/5/053002ISI: 000335383800002OAI: oai:DiVA.org:uu-224245DiVA, id: diva2:715981
Funder
Knut and Alice Wallenberg FoundationSwedish Research Council
Available from: 2014-05-07 Created: 2014-05-07 Last updated: 2018-01-12Bibliographically approved
In thesis
1. Collective properties of magnetic mesospins
Open this publication in new window or tab >>Collective properties of magnetic mesospins
2018 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Mesoscopic spin systems consist of an ensemble of lithographically patterned nanomagnetic elements - mesospins. The interactions between the mesospins, can be designed at will by altering their lateral arrangement, enabling the study of collective magnetic order in a wide range of systems.          

  The spin dimensionality of a mesospin is controlled by its shape and form. Thin elongated elements are Ising-like, with only two possible magnetization directions. Disc shaped elements can be single domain and behave XY-like, with a magnetization direction free to rotate in the plane of the disc. Larger disc sizes result in magnetic vortices. Tuning the material parameters of the elements enables mesospin dynamics at and below room temperature. Combining all of the above, the magnetic state of a lattice is then defined by the mesospins lateral arrangement, their spin dimensionality, and the temperature.          

  In this Thesis we investigate the magnetic order and dynamic properties in a series of different configurations, where the nano-magnetic elements are in the vortex state, Ising-like mesospins or of mixed mesospin dimensionality. Chains of Ising-mesospins were investigated and shown to be successfully described by the Ising model. A lossless transition between the magnetic vortex state and the collinear state, was found in square arrays of magnetic discs. In a more complicated interaction regime, square artificial spin ice, the dynamical range of the Ising-like mesospins in the lattice was probed, in terms of magnetization relaxation studies.          

  Utilizing the configurational freedom in mesoscopic spin systems, together with the possibility to alter the spin dimensionality of the elements, it is possible to create a lattice with no naturally occurring analogue. In such a lattice, where XY mesospins were added to square artificial spin ice, it was found that the degeneracy of the square ice model was restored. Furthermore, using a reciprocal space analysis tool, the magnetic spin structure factor, the system was shown to possess the characteristic features of a Coulomb spin liquid with strong local correlations and absence of long range order. Increasing the interaction between the elements, results in an emergent magnetic order on a large length-scale.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2018. p. 89
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1619
Keyword
artificial spin ice, magnetic nano-structures, mesoscopic spin systems, mesospins, mixed spin dimensionalities, interaction modifier, engineering of energy landscape, emergence
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-338722 (URN)978-91-513-0205-8 (ISBN)
Public defence
2018-03-02, Häggsalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 09:15 (English)
Opponent
Supervisors
Available from: 2018-02-06 Created: 2018-01-12 Last updated: 2018-03-08

Open Access in DiVA

fulltext(1009 kB)353 downloads
File information
File name FULLTEXT01.pdfFile size 1009 kBChecksum SHA-512
5a77cc60c67011bd39988d493450381bd6dd98f51f35cd46ebc454f125fc79270e751a57d61382e5c4fb12cc976c251ccebd51dd96c5179880a3f46c0b560c22
Type fulltextMimetype application/pdf

Other links

Publisher's full text

Search in DiVA

By author/editor
Östman, ErikArnalds, Unnar BMelander, EmilKapaklis, VassiliosPapaioannou, Evangelos ThHjörvarsson, Björgvin
By organisation
Materials Physics
In the same journal
New Journal of Physics
Condensed Matter Physics

Search outside of DiVA

GoogleGoogle Scholar
Total: 353 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 1198 hits
CiteExportLink to record
Permanent link

Direct 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