Influence of epitaxial strain on the perpendicular magnetic anisotropy of Fe/MgO systems

Perpendicular magnetic anisotropy (PMA) in ferromagnet/oxide systems has attracted considerable attention owing to its significant potential in spintronic applications; however, an understanding of the causes of PMA enhancement in such systems remains inadequate. This study investigates the influence of epitaxial strain on PMA in the Fe/MgO system. The PMA energy increases monotonically as the in-plane lattice constant of Fe decreases, and increases further after annealing. We find that the interface component of the PMA energy is largely unaffected by the epitaxial strain and annealing process, and that changes in its bulk component play an important role. This study leads to a comprehensive understanding of PMA and voltage-controlled magnetic anisotropy effects in ultrathin magnetic films.