Change search
ReferencesLink to record
Permanent link

Direct link
Initial Growth of LaFeO3 on (111)-Oriented Substrates
Norwegian University of Science and Technology, Faculty of Information Technology, Mathematics and Electrical Engineering, Department of Electronics and Telecommunications.
2013 (English)MasteroppgaveStudent thesis
Abstract [en]

Perovskite oxide thin films grown in the (111)-direction are, due to their expected novel properties resulting from the strong structural and electronic coupling, interesting for all oxide heterostructures. A prerequisite for such structures is control of growth and surface morphology. This work aims to elucidate the initial growth of LaFeO3 on (111)-oriented SrTiO3 and La0.7Sr0.3MnO3 substrates in order to investigate any differences in growth induced by the substrates. In this master thesis, initial growth of the antiferromagnet LaFeO3 by Pulsed Laser Deposition has been investigated both on (111)-oriented SrTiO3 and on three monolayer thick La0.7Sr0.3MnO3 buffer layers, the materials have been chosen due to their magnetic coupling properties. Characterization has been done with Atomic Force Microscope, in-situ Reflection High-Energy Electron Diffraction (RHEED) and X-Ray Diffraction. A study of the initial growth on SrTiO3 is presented, showing two growth regimes over the first two monolayers. The first RHEED intensity peak is observed after half as many pulses as the next, the continued growth rate is 45 laser pulses per monolayer. In the case of LaFeO3 grown on a La0.7Sr0.3MnO3 buffer layer, the RHEED oscillations show a constant growth rate of 45 laser pulses per monolayer. A possible origin for the change in RHEED period has been identified as filling of Sr- vacancies in the substrate surface. Furthermore, in order to elucidate the continued growth of LaFeO3, thicker films between 2.5 and 30nm are grown. They show an initial layer-by-layer growth mode over the first 2.5nm before transitioning into 3D island growth mode. LaFeO3 was also seen to grow smoother at low temperatures 540 degrees celcius. The (111)-oriented LaFeO3/La0.7Sr0.3MnO3 interface is interesting as it exhibit exchange coupling in the (100)-oriented interface and an increased coupling is expected in the (111)-orientation. LaFeO3/La0.7Sr0.3MnO3 heterostructures are synthesized in order to investigate the growth at a rougher interface. The films showed a good crystalline quality, but due to early roughening they had a near 3D surface at the interface and a 3D surface in the end. In-situ measurements of the surface in-plane constant showed a large change in all films were it was applied, this was attributed to a general roughening effect leading to an increased angular distribution of the RHEED beam. These investigations are important for further understanding of growth in the (111)-orientation and in preparation for further investigations of the LaFeO3/La0.7Sr0.3MnO3 interface coupling.

Place, publisher, year, edition, pages
Institutt for elektronikk og telekommunikasjon , 2013. , 85 p.
Identifiers
URN: urn:nbn:no:ntnu:diva-22564Local ID: ntnudaim:9569OAI: oai:DiVA.org:ntnu-22564DiVA: diva2:649809
Supervisors
Available from: 2013-09-19 Created: 2013-09-19 Last updated: 2013-09-19Bibliographically approved

Open Access in DiVA

fulltext(10045 kB)236 downloads
File information
File name FULLTEXT01.pdfFile size 10045 kBChecksum SHA-512
f3485501073245f958e2c54e7739254926bd7d0b9c0e8623057824ee52a077712b00f21e8e8d54d4bbff6534a0fd3998cb3f2d597fcae98e11cb87716d209761
Type fulltextMimetype application/pdf
cover(240 kB)21 downloads
File information
File name COVER01.pdfFile size 240 kBChecksum SHA-512
102a41e4149b0b1cac63c10f8513da7483e3a93decab84f2dfb25f0e3c2723b75c741a159eff75ecf8ce07fa23f09fac442491674294ad6a2f9c0347be52da3a
Type coverMimetype application/pdf
attachment(287 kB)8 downloads
File information
File name ATTACHMENT01.zipFile size 287 kBChecksum SHA-512
1ddae8af9114ffecf57fd30175767ab60c044788f680f00194be7dd96a32c882cb6c9c056542102994a2db597e1b6466316a50b78838725f3e41da9a1085364d
Type attachmentMimetype application/zip

By organisation
Department of Electronics and Telecommunications

Search outside of DiVA

GoogleGoogle Scholar
Total: 236 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

Total: 168 hits
ReferencesLink to record
Permanent link

Direct link