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arXiv · 1107.1778

Strong coupling of Sm and Fe magnetism in SmFeAsO as revealed by magnetic x-ray scattering

S. Nandi·Y. Su·Y. Xiao·S. Price·X. F. Wang·X. H. Chen·J. Herrero-Martín·C. Mazzoli·H. C. Walker·L. Paolasini·S. Francoual·D. K. Shukla·J. Strempfer·T. Chatterji·C. M. N. Kumar·R. Mittal·H. M. Rønnow·Ch. Rüegg·D. F. McMorrow·Th. Brückel
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Abstract

The magnetic structures adopted by the Fe and Sm sublattices in SmFeAsO have been investigated using element specific x-ray resonant and non-resonant magnetic scattering techniques. Between 110 and 5 K, the Sm and Fe moments are aligned along the c and a directions, respectively according to the same magnetic representation $\Gamma_{5}$ and the same propagation vector (1, 0, 0.5). Below 5 K, magnetic order of both sublattices change to a different magnetic structure and the Sm moments reorder in a magnetic unit cell equal to the chemical unit cell. Modeling of the temperature dependence for the Sm sublattice as well as a change in the magnetic structure below 5 K provide a clear evidence of a surprisingly strong coupling between the two sublattices, and indicate the need to include anisotropic exchange interactions in models of SmFeAsO and related compounds.

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S. Nandi, Y. Su, Y. Xiao, S. Price, X. F. Wang, X. H. Chen, J. Herrero-Martín, C. Mazzoli, H. C. Walker, L. Paolasini, S. Francoual, D. K. Shukla, J. Strempfer, T. Chatterji, C. M. N. Kumar, R. Mittal, H. M. Rønnow, Ch. Rüegg, D. F. McMorrow, Th. Brückel. 2011-07-09. Strong coupling of Sm and Fe magnetism in SmFeAsO as revealed by magnetic x-ray scattering. https://doi.org/10.1103/physrevb.84.054419

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