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Thermal Stability of Defects in Substrates for Multiferroic Materials

Published online by Cambridge University Press:  26 February 2011

Shehnaz Jeddy
Affiliation:
sjeddy@uab.edu, university of alabama at birmingham, physics, birmingham, AL, 35294, United States
Mary Ellen Zvanut
Affiliation:
mezvanut@uab.edu, University of Alabama at Birmingham, Physics, Birmingham, AL, 35294, United States
Brian Einstein Lassiter
Affiliation:
lassiterbrian@yahoo.com, University of Idaho, Materials Science and Engineering, Moscow, ID, 83844, United States
Gregg M Janowski
Affiliation:
janowski@uab.edu, University of Alabama at Birmingham, Materials Science and Engineering, Birmingham, AL, 35294, United States
Leonard J Brillson
Affiliation:
brillson.1@osu.edu, Ohio State University, Department of Physics and Center for Materials Research, Columbus, OH, 43210, United States
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Abstract

Strontium Titanate (STO) substrates were studied by electron paramagnetic resonance (EPR) spectroscopy to assess possible changes incurred by deposition of multiferroic thin films. To this effect, STO was vacuum annealed at pressures of 10−5 Torr for one hour at temperatures in the range of 200 – 500 °C. EPR spectra, measured before and after each anneal, revealed changes in the amount of three different defects, Cr3+, Fe3+ and an iron-oxygen vacancy complex, Fe3+Vo. The latter was used to monitor the diffusion of oxygen. EPR analysis showed that Fe3+Vo increases from its as-grown value, suggesting that a charged oxygen species is mobile in the substrate under film deposition conditions. Coupled with a subsequent O2 anneal showing minimal change in the Fe3+Vo signal, the data indicate a loss of oxygen from the sample during vacuum annealing. As charged oxygen vacancies may affect the substrate as well as the substrate/ thin film interface, these results are important for understanding the behavior of multiferroic devices built on STO substrates.

Type
Research Article
Copyright
Copyright © Materials Research Society 2007

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References

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