Magnetic properties in the normal state of LuNi2B2C observed by Ni-61 and B-11 NMR

The Ni-61 spin-lattice relaxation rate, T-61(1)-1, and the Knight shift of a 91%, Ni-61 enriched sample of LuNi2B2C have been measured in the normal state. It was found that (61)(T1T)(-1) shows a Curie-Weiss like behavior, while the Knight shift has a slight temperature dependence. The hyperfine coupling constant is estimated to be (61)A = -16 kOe/mu(B), which is an order of magnitude smaller than that due to the 3d-core-polarization mechanism. When the orbital term of the relaxation rate is given by the formula calculated for the tetragonal (D-2d) symmetry at the Ni-61 sites, much larger d-spin term than that expected from the Knight shift is obtained. The Korringa relation is also discussed on the assumption that the hyperfine coupling constant is reduced by a strong s-d admixture, and then the deviation from the Korringa relation for free electrons, K(alpha), is more than one. This result suggests the significance of the generalized susceptibility, chi(q), at finite wave vectors.