Nuclear magnetic relaxation in YNi2-xPtxB2C

The temperature dependence of C-13 spin-lattice relaxation time T-1 in YNi2 -xPtxB2C (x = 0 and 0.8) has been measured. With decreasing temperature the relaxation rate 1/T-1 forms a Hebel-Slichter peak just below T-c and after that it decreases exponentially with the gap parameter 2 Delta(0) = 4.8 k( B) T-c. Below about 4 K it starts to vary linearly with T, where the values of 1/T1T were proportional to H-0, the observing magnetic field. This mean s that the spin diffusion to normal cores is important for the relaxation. These results support the model of the phonon-mediated superconductivity in this system. (C) 2000 Elsevier Science B.V. All rights reserved.