AL-27 NMR AND NQR STUDIES OF THE ANTIFERROMAGNETIC SUPERCONDUCTOR UPD2AL3

We present measurements of the NQR and NMR spectra and the nuclear rel axation rate, 1/T-1, of Al-27 in UPd2Al3 from 0.06 K to 270 K. The bro adening of NQR lines and the rapid decrease of 1/T-1 below 14K indicat e the appearance of antiferromagnetic order. The temperature dependenc e of 1/T-1 in the superconducting state shows the existence of line no des in the superconducting energy gap, and also the existence of resid ual density of states arising from strong resonant scattering by non-m agnetic impurities or imperfections. Together with the decrease of the Knight shift in the superconducting state, it is expected that d-wave superconductivity appears in UPd2Al3.