GaNMR/NQR study in UGa3

Microscopic magnetic properties of a uraniun intermetallic compound, UGa3 ( T-N = 67 K), have been investigated by the Ga-69 and Ga-71 NMR;NQR measurem ents. We found a drastic temperature (T-) dependence of the NQR spectrum ne ar TN, in which a single Ga-69 NQR line of 19.8 MHz in the paramagnetic sta te rapidly vanishes at 70 K and a double peak appears at 17.2 and 16.55 MHz between 63 and 70 K. This result is significantly different from the case of the usual antiferromagnetic ordering, and suggests a transient modificat ion of the electric field gradient at the Ga sites. The Ga nuclear spin-lat tice relaxation rate T-1(-1) in the paramagnetic state shows local characte r for spin fluctuations of 5f-electrons rather than 5f-itinerant behavior. (C) 2001 Elsevier Science B.V. All rights reserved.