Large perpendicular magnetic anisotropy in epitaxial Fe/MgAl2O4(001) heterostructures

We investigated the perpendicular magnetic anisotropy (PMA) and related properties of epitaxial Fe (0.7 nm)/MgAl2O4 (001) heterostructures prepared by electron beam evaporation. Using an optimized structure, we obtained a large PMA energy of MJ/m(3) at room temperature, which is comparable to that in ultrathin-Fe/MgO(001) heterostructures. Both the PMA energy and saturation magnetization showed a weak temperature dependence, ensuring a wide working temperature range in applications. The effective magnetic damping constant of the 0.7 nm Fe layer was found to be -41.02 using the time-resolved magneto-optical Kerr effect. This study demonstrated the suitability of the Fe/MgAl2O4 heterostructure for use in perpendicular magnetic tunnel junctions, as well as good agreement with theoretical predictions. (C) 2018 The Japan Society of Applied Physics