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arXiv · 1103.1039

Low-moment magnetism in the double perovskites Ba2MOsO6 (M=Li,Na)

Andrew J. Steele·Peter J. Baker·Tom Lancaster·Francis L. Pratt·Isabel Franke·Saman Ghannadzadeh·Paul A. Goddard·William Hayes·D. Prabhakaran·Stephen J. Blundell
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Abstract

The magnetic ground states of the isostructural double perovskites Ba$_2$NaOsO$_6$ and Ba$_2$LiOsO$_6$ are investigated with muon-spin rotation. In Ba$_2$NaOsO$_6$ long-range magnetic order is detected via the onset of a spontaneous muon-spin precession signal below $T_{\mathrm{c}}=7.2\pm 0.2\;\mathrm{K}$, while in Ba$_2$LiOsO$_6$ a static but spatially-disordered internal field is found below 8 K. A novel probabilistic argument is used to show from the observed precession frequencies that the magnetic ground state in Ba$_2$NaOsO$_6$ is most likely to be low-moment ($\approx 0.2$\,$μ_{\rm B}$) ferromagnetism and not canted antiferromagnetism. Ba$_2$LiOsO$_6$ is antiferromagnetic and we find a spin-flop transition at 5.5\,T. A reduced osmium moment is common to both compounds, probably arising from a combination of spin-orbit coupling and frustration.

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Andrew J. Steele, Peter J. Baker, Tom Lancaster, Francis L. Pratt, Isabel Franke, Saman Ghannadzadeh, Paul A. Goddard, William Hayes, D. Prabhakaran, Stephen J. Blundell. 2011-11-08. Low-moment magnetism in the double perovskites Ba2MOsO6 (M=Li,Na). https://doi.org/10.1103/physrevb.84.144416

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