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arXiv · 1504.04425

Twisted phase of the orbital-dominant ferromagnet SmN in a GdN/SmN heterostructure

J. F. McNulty·E. -M. Anton·B. J. Ruck·F. Natali·H. Warring·F. Wilhelm·A. Rogalev·M. Medeiros Soares·N. B. Brookes·H. J. Trodahl
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Abstract

The strong spin-orbit interaction in the rare-earth elements ensures that even within a ferromagnetic state there is a substantial orbital contribution to the ferromagnetic moment, in contrast to more familiar transition metal systems, where the orbital moment is usually quenched. The orbital-dominant magnetization that is then possible within rare-earth systems facilitates the fabrication of entirely new magnetic heterostructures, and here we report a study of a particularly striking example comprising interfaces between GdN and SmN. Our investigation reveals a twisted magnetization arising from the large spin-only magnetic moment in GdN and the nearly zero, but orbital-dominant, moment of SmN. The unusual twisted phase is driven by (i) the similar ferromag- netic Gd-Gd, Sm-Sm and Gd-Sm exchange interactions, (ii) a SmN Zeeman interaction 200 times weaker than that of GdN, and (iii) the orbital-dominant SmN magnetic moment. The element specificity of X-ray magnetic circular dichroism (XMCD) is used in seperate modes probing both bulk and surface regions, revealing the depth profile of the twisting magnetization.

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J. F. McNulty, E. -M. Anton, B. J. Ruck, F. Natali, H. Warring, F. Wilhelm, A. Rogalev, M. Medeiros Soares, N. B. Brookes, H. J. Trodahl. 2015-04-17. Twisted phase of the orbital-dominant ferromagnet SmN in a GdN/SmN heterostructure. https://doi.org/10.1103/physrevb.91.174426

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