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arXiv · 1701.09171

Valence state of Sm in single crystalline EuO thin films

A. Reisner·D. Kasinathan·S. Wirth·L. H. Tjeng·S. G. Altendorf
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Abstract

Samarium has two stable valence states, 2+ and 3+, which coexist in many compounds forming spatially homogeneous intermediate valence states. We study the valence state of samarium when incorporated in a single crystalline EuO thin film which crystallizes in a $fcc$-structure similar to that of the intermediate valence SmO, but with a larger lattice constant. Due to the increased lattice spacing, a stabilization of the larger Sm$^{2+}$ ion is expected. Surprisingly, the samarium incorporated in Sm$_{\mathrm{x}}$Eu$_{\mathrm{1-x}}$O thin films shows a predominantly trivalent character, as determined by x-ray photoelectron spectroscopy and magnetometry measurements. We infer that the O$^{2-}$ ions in the EuO lattice have enough room to move locally, so as to reduce the Sm-O distance and stabilize the Sm$^{3+}$ valence.

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A. Reisner, D. Kasinathan, S. Wirth, L. H. Tjeng, S. G. Altendorf. 2017-01-31. Valence state of Sm in single crystalline EuO thin films. https://doi.org/10.1209/0295-5075%2F117%2F47001

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