Abstract
This paper presents quenched molecular dynamics simulations of the vacancy behavior near the surface of an ordered CoPt alloy. The formation, migration, and activation energies are deduced for the different atoms (Co and Pt), moving in and between the different planes parallel to the surface. The migration of an adatom at the surface is also studied. The alloy surface is preferentially a Pt plane. There are typically two planes where the migration and formation energies are different from the bulk. The anisotropy of the structure involves an anisotropy of the diffusion. The values of the energies obtained for the different processes are used to understand the chemical ordering in CoPt(001) thin films grown at different temperatures. These films present indeed a concentration modulation along the growth direction with 2 temperature ranges. We analyze this behavior in terms of chemical ordering using a classical phenomenological diffusion law with the values of the energies deduced by quenched molecular dynamics.
- Received 26 October 2007
DOI:https://doi.org/10.1103/PhysRevB.78.035429
©2008 American Physical Society