INFLUENCE OF BULK DIFFUSION ON DROPLET GROWTH IN BINARY-SYSTEMS WITH A NONCONSERVED ORDER-PARAMETER

On the basis of a Ginzburg-Landau-type description we consider the growth of droplets from a metastable state in binary systems with a non-conserved order parameter coupled to a diffusive non-ordering field. A simple example of such a system is a uniaxial antiferromagnet with energy conservation. It turns out that the growth properties crucially depend on the jump of the non-ordering density between the inside and outside regions of droplets. If there is no jump the processes of droplet growth and bulk diffusion decouple. With increasing value of the jump we observe in the single-droplet growth a crossover to a behaviour expected for a system with a conserved order parameter. We also find a Mullins-Sekerka instability of the growing droplet caused by the competition between surface tension and bulk diffusion. The effect of diffusive interactions between different droplets is discussed for the simplest case of a two-droplet configuration.