SPIN-LATTICE RELAXATION IN PHASE-SEPARATED HE-3-HE-4 SOLID-SOLUTION

The spin-lattice relaxation time in a He-3-He-4 solid solution with th e initial concentration 3.18%He-3 is measured during phase separation by using the pulsed NMR technique. The relaxation time in a concentrat ed bbc phase formed as a result of phase separation is found to be ind ependent of temperature over the entire range of its existence and is determined by the Zeeman-exchange interaction mechanism. In the dilute hcp daughter phase, the spin-lattice relaxation time increases on coo ling according to the law T-1 similar to x(-n), where n=0.88+/-0.12, a nd x is the He-3 concentration. The values of T-1 in this phase coinci de with the values corresponding to a homogeneous (nonseparated) solut ion of the same concentration. (C) 1997 American Institute of Physics.