NMR/NQR studies of U-123 type heavy fermion compounds

NQR and NMR measurements have been performed for two types of heavy fermion compounds, UNi2Al3 (T-N=4.6 K, T-c=1 K) and UPd2Ga3 (T-N=13 K). In UNi2Al3, an appreciably broadened Al-27-NQR spectrum was observed below T-N, indicating that the magnetic structure is not the planar type such as UPd2Al3, but an incommensurate spin density wave or helical type one. In the superconducting state, 1/T-1 decreases with no coherence peak just below T-c, similarly to the other heavy fermion superconductors. In UPd2Ga3, two well-separated sets of Ga-NQR spectra were observed in the paramagnetic state, implying that Ga atoms occupy two different sites.