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arXiv · 1709.09827

Magnetic states at the surface of alpha-Fe2O3 thin films doped with Ti, Zn or Sn

David S. Ellis·Eugen Weschke·Asaf Kay·Daniel A. Grave·Kirtiman Deo Malviya·Hadar Mor·Frank M. F. de Groot·Hen Dotan·Avner Rothschild
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Abstract

The spin states at the surface of epitaxial thin films of hematite, both undoped and doped with 1% Ti, Sn or Zn, respectively, were probed with x-ray magnetic linear dichroism (XMLD) spectroscopy. Morin transitions were observed for the undoped (T_M~200 K) and Sn-doped (T_M~300 K) cases, while Zn and Ti-doped samples were always in the high and low temperature phases, respectively. In contrast to what has been reported for bulk hematite doped with the tetravalent ions Sn4+ and Ti4+, for which T_M dramatically decreases, these dopants substantially increase T_M in thin films, far exceeding the bulk values. The normalized Fe LII-edge dichroism for T T_M state was achieved. The temperature dependence of the critical field for the Sn-doped sample was characterized in detail. It was demonstrated the sample-to-sample variations of the Fe LIII-edge spectra were, for the most part, determined solely by the spin orientation state. Calculations of the polarization-depedent spectra based on a spin-multiplet model were in reasonable agreement with the experiment and showed a mixed excitation character of the peak structures.

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David S. Ellis, Eugen Weschke, Asaf Kay, Daniel A. Grave, Kirtiman Deo Malviya, Hadar Mor, Frank M. F. de Groot, Hen Dotan, Avner Rothschild. 2017-09-28. Magnetic states at the surface of alpha-Fe2O3 thin films doped with Ti, Zn or Sn. https://doi.org/10.1103/physrevb.96.094426

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