Effects of composition and chemical disorder on the magnetocrystalline anisotropy of Fe_xPt_1−x alloys

¹ Department of Physics, University of York - York YO10 5DD, UK
² Department of Theoretical Physics and Condensed Matter Research Group of Hungarian Academy of Sciences, Budapest University of Technology and Economics - Budafoki út 8., H1111 Budapest, Hungary

Received: 8 April 2013
Accepted: 24 May 2013

Abstract

We perform first-principles calculations of the magnetocrystalline anisotropy energy (MAE) of the L1₀-like Fe_xPt_1−x samples studied experimentally by Barmak and co-workers (see J. Appl. Phys., 98 (2005) 033904). The variation of composition and long-range chemical order in the samples was studied in terms of the coherent potential approximation. In accordance with experimental observations, we find that, in the presence of long-range chemical disorder, Fe-rich samples exhibit a larger MAE than stoichiometric FePt. By considering the site-and species-resolved contributions to the MAE, we infer that the MAE is primarily a function of the degree of completeness of the nominal Fe layers in the L1₀ FePt structure.