B-11 AND PT-195 NMR-STUDIES IN THE NORMAL-STATE OF SUBSTITUTED BOROCARBIDE SUPERCONDUCTORS Y0.98ER0.02NI2B2C AND LAPT1.5AU0.6B2C

We report, B-11 NMR studies on Y0.98Er0.02Ni2B2C and B-11 and Pt-195 N MR studies on LaPt1.5Au0.6B2C superconductors. The variation of (1/T1T ) with temperature in the normal state of Y0.98Er0.02Ni2B2C shows a si milar behaviour as in YNi2B2C. However, its magnitude is one order mor e than that observed in YNi2B2C. This suggests that T-1 is dominated b y the thermal fluctuations of Er local moments in this case. From B-11 and Pt-195 NMR in LaPt1.5Au0.6B2C, we demonstrate that the Pt 5d band is full and the compound exhibits Korringa behaviour as expected for a normal Fermi-liquid. This is in contrast to YNi2B2C where an enhance ment of the B-11 (1/T1T) is observed at low temperatures along with a deviation from Korringa behaviour, suggesting that the enhancement see n in YNi2B2C could be due to the anti-ferromagnetic fluctuations from nickel 3d-electrons.