Perpendicular magnetic anisotropy at lattice-matched Co_2FeAI/MgAI_2O_4(001) epitaxial interfaces

摘要

We report perpendicular magnetic anisotropy (PMA) induced at Co_2FeAl/MgAl_2O_4(001) epitaxial interfaces prepared by magnetron sputtering and post-oxidation of MgAl layers. A PMA energy density of more than 4 Merg/cm~3 for 1-nm-thick Co_2FeAl layers and an effective interface PMA energy density of 1.6 erg/cm~2 were achieved by controlling the interfacial oxidation states through fine-tuning of oxidation processes and annealing temperature. Cross-sectional scanning transmission electron microscopy imaging revealed a lattice-matched Co_2FeAl/MgAl_2O_4 interface, which may be responsible for the large PMA energy due to a reduction of the bulk anisotropy contribution.