Journal of Low Temperature Physics, Vol. 75, Nos. I/2, 1989 The Growth Rate of 3He Crystals

We have measured the relaxation of the shape of 3He crystals under the effect of gravity and surface tension, close to the minimum in their melting curve at Train = 0.32 K. A growth rate is deduced, which is found to be at a maximum at Train when the latent heat is zero. We interpret his maximum value (k = 0.18~O.04 sec/m) as the intrinsic mobility of the liquid-solid interface and compare it with existing theories. We also consider on which side the latent heat is released uring growth, and how it may cross the liquid-solid interface. We report the first direct measurement of k, the intrinsic growth rate of 3He crystals or intrinsic mobility of the interface between liquid and solid 3He. When the temperature is homogeneous in the whole system, and if the surface is rough 1'2, k is the ratio of the growth velocity v to the difference in chemical potential A/z =/xL--~s between the liquid and the solid (/x is taken per unit mass). In ordinary systems, it is generally difficult to have access to this quantity. Indeed, when a pure crystal is grown from its melt, the growth velocity is mainly limited by the slow diffusion of th