Finite-Size Effects on First-Order Phase Transitions: fcc Binary Alloys

Abstract
Size effects in fcc binary alloys undergoing a bulk first-order phase transition are investigated in the limit of very thin films. The interplay between surface segregation and spatial ordering is studied by means of a discrete model in the Bragg-Williams approximation. Concentration and long-range-order-parameter profiles in the film are calculated for equilibrium and for metastable states. Results for the thickness dependence of the transition temperature and of the discontinuity of the order parameter are presented.