Zero- and longitudinal-field muon spin depolarization measurements of CeNiSn

We report on zero- and longitudinal-held muon spin depolarization measureme nts performed on single crystals of the Kondo insulator CeNiSn. The initial muon beam polarization is parallel to the a crystal axis. Going down in te mperature, we observe in zero field a monotonous increase of the exponentia l damping rate starting at similar to 20 K. In longitudinal field measureme nts the damping rate drops to zero at a few mT, reflecting a quasi-static f ield distribution at the muon site. Contrary to previously published result s, our data do not allow to safely determine whether the observed increase of depolarization at low temperature originates from the electronic-magneti c correlations or from nuclear magnetic moments of the compound. (C) 2000 E lsevier Science B.V. All rights reserved.