A comprehensive study of O17 nuclear spin-lattice relaxation in NpO2 is reported for a wide range of fields and temperatures. In both the paramagnetic and ordered-state regions, a strong, field-dependent cross-relaxation process is observed in addition to the expected background rate. The cross-relaxation process, driven by the Np237 spins, is conveyed to the O17 via a greatly enhanced indirect nuclear spin-spin coupling. The magnitude and temperature dependence of the indirect coupling are in reasonable accord with a simple theoretical model. The magnitude and temperature dependence of the Np237 T1 process are also deduced from the data obtained.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2006|