NMR Study of Magnetic Excitations in CeNiSn

Abstract

The anisotropies of the Knight shift and the nuclear spin-lattice relaxation time ( T 1 ) at the Sn sites have been measured up to 300 K with a magnetically aligned powder sample of CeNiSn. In contrast to the results of previous neutron scattering measurements, the anisotropy of 1/ T 1 is weak and almost temperature ( T )-independent. This indicates that the substantial spectral weight exists in the higher energy region than the quasielastic magnetic excitation at high T . Above about 60 K, 1/ T 1 increases linearly with T , suggesting that the T dependence of the quasielastic line width is weak.