Anomalous spin-lattice relaxation in solid3He

Nuclear spin-lattice relaxation measurements have been carried out in bcc and hcp solid³He at low temperatures. The observed relaxation rates are anomalously high and indicate that a typical sample has a substructure of small domains at whose boundaries rapid spin-lattice equilibrium takes place. Experiments on the sample anisotropy show that these domains cannot be crystallites and we believe that they may be determined by stacking faults or small-angle grain boundaries. The magnetic field dependence of the spin diffusion coefficient and the effects of dissolved⁴He are also investigated.