Low-temperature magnetic fluctuations in the Kondo insulator SmB6
  We present the results of a systematic investigation of the magnetic properties of the three-dimensional Kondo topological insulator SmB6 using magnetization and muon-spin relaxation/rotation (muSR) measurements. The muSR measurements exhibit magnetic field fluctuations in SmB6 below 15 K due to electronic moments present in the system. However, no evidence for magnetic ordering is found down to 19 mK. The observed magnetism in SmB6 is homogeneous in nature throughout the full volume of the sample. Bulk magnetization measurements on the same sample show consistent behavior. The agreement between muSR, magnetization, and NMR results strongly indicate the appearance of intrinsic bulk magnetic in-gap states associated with fluctuating magnetic fields in SmB6 at low temperature. 
P. K. Biswas, Z. Salman, T. Neupert, E. Morenzoni, E. Pomjakushina, F.   von Rohr, K. Conder, G. Balakrishnan, M. Ciomaga Ha...
cond-mat.str-el