PD-105 NMR AND NQR STUDIES IN HEAVY-FERMION SUPERCONDUCTOR UPD2AL3

Pd-105 NMR and NQR measurements have been performed both in the normal and in the superconducting states for UPd2Al3. In the antiferromagnet ically (AF) ordered state, a small internal field of about 3 kOe (at 4 .2 K), which is perpendicular to the c-axis, appears below 14.5 K and does not decrease in the superconducting state. The nuclear spin-latti ce relaxation rate, 1/T-1, in UPd2Al3 is nearly temperature, T, indepe ndent in the paramagnetic state up to 60 K, successively diverges at t he Ni el temperature associated with the critical slowing down of U ma gnetic moments, and then decreases markedly in the AF ordered state. I n the superconducting state, 1/T-1 decreases in proportion to T-3 down to 0.5 K with no coherence peak just below T-c, which indicates the o ccurrence of anisotropic superconductivity having line nodes in the su perconducting energy gap. (C) 1998 Elsevier Science B.V. All rights re served.