TIME CONSTANT OF ISOTOPIC PHASE-SEPARATION IN HCP HE-3-HE-4 MIXTURES - MASS QUANTUM DIFFUSION ROLE

Experimental and theoretical study of the growth kinetics of BCC He-3 precipitates in isotopic phase separation of HCP He-3-He-4 is carried out. Low frequency pulsed NMR is used to study the mixture with an ini tial concentration of 3.18% of He-3 at a pressure 3.7 MPa during stepp ed cool down into the separation region. The separation time constant is shown to decrease monotonically with cooling. The evolution of hete rophase. structure resulted from decay is investigated by solving the equation for spatially nonhomogeneous order parameter of decomposing m ixture. The obtained temperature dependence of separation time constan t is found to be in good agreement with experiment.