K. Matsuda et al., OBSERVATION OF PD-105 NMR AND NQR SIGNALS IN THE HEAVY-FERMION SUPERCONDUCTOR UPD2AL3, Physical review. B, Condensed matter, 55(22), 1997, pp. 15223-15227
Pd-105 NMR and NQR measurements have been performed both in the normal
and in the superconducting states for the heavy-fermion superconducto
r UPd2Al3. The magnitude of the internal field at Pd is found to be ab
out 3 kOe (at 4.2 K) in the antiferromagnetically (AF) ordered state.
The nuclear spin-lattice relaxation rate, 1/T-1, in UPd2Al3 is nearly
temperature, T, independent in the paramagnetic state up to 60 K, succ
essively diverges at Neel temperature associated with the critical slo
wing down of U magnetic moments, and then decreases markedly in the AF
ordered state, which is well explained by a localized moment picture.
These results have shown that Pd atoms are nonmagnetic, in which 4d e
lectrons couple very weakly to U moments. In 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 occurrence of anisotropic su
perconductivity having line nodes in the superconducting energy gap. T
he coexistence of the AF ordering and the anisotropic superconductivit
y in UPd2Al3 could unambiguously be confirmed.