EVOLUTION OF THE CONCENTRATED PHASE IN SEPARATED SOLID HE-3-HE-4 MIXTURES

Experimental and theoretical investigations of the growth kinetics of BCC He-3 precipitates in isotopic phase separation of HCP He-3-He-4 ar e carried out. Low frequency pulsed NMR is used to study the mixture w ith an initial 3He concentration of 3.18% at a pressure 3.7 MPa on ste pped cooling down into the separation region. The separation time cons tant is shown to decrease monotonically,vith cooling. The evolution of heterophase structure resulted from separation is investigated by sol ving an equation for spatially non-homogeneous order parameter of deco mposing mixture. The obtained temperature dependence of separation tim e constant is found to be in good agreement with the experiment.