Abstract
The Morin transition of very thin Ir-doped α-Fe2O3 films, which is not detectable with conventional magnetization measurements, was studied by conversion electron Mössbauer spectroscopy using a 57Co source and nuclear resonant scattering using a synchrotron light source. It was found that (i) the Morin transition temperature increases as the Ir ratio increases, (ii) it decreases when the film thickness decreases, and (iii) the transition becomes irreversible when Ir ratio is small and the thickness is thin. These tendencies were found reproducible and systematic, although the mechanisms are to be clarified by further studies.
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Acknowledgments
The authors would like to thank Dr. M. Sahashi, Dr. T. Nozaki, and Dr. T. Mitsui for fruitful discussion. The nuclear resonant scattering measurements were performed at BL09XU in SPring-8 (Proposal numbers 2016A0906, 2016B0906, and 2017A0906). These series of works were financially supported by ImPACT Program of Council for Science Technology, and Innovation from Cabinet Office, Japan, Grants-in-Aid for Scientific Research (B) (Grant number 25287086) and (S) (Grant number 24221005) from Japan Society for the Promotion of Science (JSPS) and MEXT, Japan, and a Grant-in-Aid from the Hori Sciences And Arts Foundation.
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This article is part of the Topical Collection on Proceedings of the International Conference on the Applications of the Mössbauer Effect (ICAME 2017), Saint-Petersburg, Russia, 3-8 September 2017
Edited by Valentin Semenov
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Mibu, K., Mikami, K., Tanaka, M. et al. Thickness dependence of Morin transition temperature in iridium-doped hematite layers studied through nuclear resonant scattering. Hyperfine Interact 238, 92 (2017). https://doi.org/10.1007/s10751-017-1470-2
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DOI: https://doi.org/10.1007/s10751-017-1470-2