Effect of Pt impurities on the magnetocrystalline anisotropy of hcp Co: a first-principles study

摘要

In terms of the fully relativistic screened Korringa-Kohn-Rostoker method weinvestigate the variation in the magnetocrystalline anisotropy energy (MAE) ofhexagonal close-packed cobalt with the addition of platinum impurities. Inparticular, we perform calculations on a bulk cobalt system in which one of theatomic layers contains a fractional, substitutional platinum impurity. Ourcalculations show that at small concentrations of platinum the MAE is reduced,while at larger concentrations the MAE is enhanced. This change of the MAE canbe attributed to an interplay between on-site Pt MAE contributions and inducedMAE contributions on the Co sites. The latter ones are subject to pronounced,long-ranged Friedel-oscillations that can lead to significant size effects inthe experimental determination of the MAE of nano-sized samples.