NMR study of the superconductor RNi(2)B(2)C (R=Y,Lu)

Abstract

Measurements of the B-11 NMR spectrum and spin-lattice relaxation rate, 1/T-1 in the normal and the superconducting stares of a quaternary boro-carbide superconductor RNi(2)B(2)C (R = Y, Lu) are reported. In the superconducting stale, two kinds of B-11 NMR spectra have been observed; one B-11 signal comes from the superconducting region in the sample and shifts to higher magnetic field due to the demagnetizing field, the other from the normal-metal region with no appreciable shifts. With decreasing temperature, 1/T, in the superconducting state decreases rapidly with no appreciable enhancement just below T-c. In the normal slate, 1/T1T increases with decreasing temperature presumably due to antiferromagnetic Ni spin fluctuations. Similar behaviors on B NMR in RNi(2)B(2)C (R = Y, Lu) were observed in the normal and the superconducting states.