Magnetic anisotropy of ultrathin Pd4Co(111) film by first-principles calculations

The Pd-Co alloy is a suitable candidate for the perpendicular magnetic recording and related applications. However, no research is available to clarify influences of local structures on the magnetic anisotropy of the Pd-Co alloy. Therefore, in this work, we studied the effects of Co arrangement on the magnetic anisotropy of ultrathin Pd4Co(111) film with 20% Co content by using the density functional theory calculations. We found that a Co monolayer in the surface layer of the ultrathin film offers a large in-plane magnetic anisotropy while the Co atoms mixed inside the Pd matrix exhibit the perpendicular magnetic anisotropy. Notably, a Co monolayer beneath the surface layer of the Pd matrix maximizes the perpendicular magnetic anisotropy up to 1.85 erg/cm2. Electronic properties were also analyzed to clarify the magnetic anisotropy of the ultrathin film.