Surface effects on order-disorder transition of binary alloys: A Monte Carlo study of PtNi

Abstract

We have studied the relation between surface segregation and surface ordering of PtNi single crystal alloys, through Monte Carlo simulation of an Ising model. Our results well explain the surface segregation on the low-index surfaces as previously observed in experimental studies. The (100) and (111) surfaces are enriched with platinum atoms and (110) surface is enriched with nickel atoms. And the segregation is quite oscillatory decaying into the bulk. Furthermore, we suggest that (100) surface would show surface-induced ordering, while (111) surface would show surface-induced disordering.