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) SmB_{6}. Results on Al-flux-grown SmB_{6} single crystals are compared to those on a large floating-zone-grown ^{154}Sm ^{11}B_{6} 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 quasistatic magnetism due to rare-earth impurities and Sm vacancies.
View Article and Find Full Text PDFWe report low-temperature muon spin relaxation/rotation (SR) measurements on single crystals of the actinide superconductor UTe. Below 5 K we observe a continuous slowing down of magnetic fluctuations that persists through the superconducting transition temperature ( = 1.6 K), but we find no evidence of long-range or local magnetic order down to 0.
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