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arXiv · 1905.08769

Intrinsic Low-Temperature Magnetism in SmB6

S. Gheidi·K. Akintola·A. M. Cote·S. R. Dunsiger·C. Broholm·W. T. Fuhrman·S. R. Saha·J. Paglione·J. E. Sonier
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Abstract

By means of new muon spin relaxation experiments, we disentangle extrinsic and intrinsic sources of low-temperature bulk magnetism in the candidate topological Kondo insulator (TKI) SmB6. Results on Al-flux grown SmB6 single crystals are compared to those on a large floating-zone grown ^{154}Sm^{11}B6 single crystal in which a 14 meV bulk spin exciton has been detected by inelastic neutron scattering. Below ~ 10 K we detect the gradual development of quasi-static magnetism due to rare-earth impurities and Sm vacancies. Our measurements also reveal two additional forms of intrinsic magnetism: 1) underlying low-energy (~ 100 neV) weak magnetic moment (~ 10^{-2} mu_B) fluctuations similar to those detected in the related candidate TKI YbB12 that persist down to millikelvin temperatures, and 2) magnetic fluctuations consistent with a 2.6 meV bulk magnetic excitation at zero magnetic field that appears to hinder surface conductivity above ~ 4.5 K. We discuss potential origins of the magnetism.

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S. Gheidi, K. Akintola, A. M. Cote, S. R. Dunsiger, C. Broholm, W. T. Fuhrman, S. R. Saha, J. Paglione, J. E. Sonier. 2019-12-12. Intrinsic Low-Temperature Magnetism in SmB6. https://doi.org/10.1103/physrevlett.123.197203

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