Nuclear magnetic resonance studies of CePd2In and LaPd2In at low temperatures

Abstract

We report on In nuclear magnetic resonance (NMR) and nuclear quadrupolar resonance (NQR) measurements on the new heavy-electron compound CePdZIn over a wide temperature range, from 45 mK up to 30 K. CePd2In undergoes an antiferromagnetic (AF) phase transition at TN = 1.23 K involving small localised Ce moments of 0.11 μB. In zero field, the spin-lattice relaxation rate T1−1 (T) shows remarkable changes in its temperature dependence. Above 3 K, T1−1 is constant and 850 sec−1. Between TN and 2TN, (T1T)−1 = 330 (Ksec)−1, but rapidly decreases below TN. A Korringatype relaxation, characteristic for simple metals at low temperatures, with (T2T)−1 = 17(Ksec)1 is resumed below 0.6 K. This value is an order of magnitude larger than (T1T)−1 for LaPd2In and therefore is associated with low-energy excitations of the itinerant charge carriers with 4f symmetry. The T1−1 data at various non-zero magnetic fields fall on a single curve when plotted as a function of (T/H) if H exceeds 3.5 T. Thus the AF ordering, the 4f moment fluctuations and the Kondo screening are drastically suppressed by the application of fields H of the order of 3.5 T.