NMR studies of U0.2Y0.8Pd3 and YPd3 at low temperatures

We report results of 89Y-NMR measurements on U0.2Y0.8Pd3 as well as YPd3, performed at frequencies between 9 and 16 MHz and at temperatures between 0.25 and 2 K. In this temperature range the average Knight shift is +0.5%, temperature-independent and the same for both materials. Also the NMR linewidth for both compounds was found to be temperature and field independent but one order of magnitude larger for U0.2Y0.8Pd3 than for YPd3. For U0.2Y0.8Pd3 our results indicate a distribution of internal static fields at the Y sites and a small temperature-dependent enhancement of the spin-lattice relaxation rate T1-1 with respect to YPd3. The NMR spectra are consistent with the presence of very small frozen U moments, but the temperature dependence of the spin-lattice relaxation rate indicates a more complicated situation. In particular (T1T)-1 shows an anomalous temperature dependence. (orig.)