Phase-separation kinetics of He-3-He-4 solid solutions at various degrees of supersaturation

The phase-separation kinetics of He-3-He-4 solid solutions at various degre es of supersaturation Delta x are studied using precise pressure measuremen ts. It is found that the characteristic phase-separation times do not depen d on the degree of supersaturation but are determined by the final temperat ure to which the crystal is cooled. The behavior of the effective diffusion coefficient, which governs the corresponding mass transfer, cannot be desc ribed within the impuriton model of the mobility of He-3 atoms in a He-4 cr ystal. (C) 1999 American Institute of Physics. [S1063- 7834(99)03111-1].