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

TL;DR

This study demonstrates that epitaxial Fe/MgAl2O4(001) heterostructures exhibit large perpendicular magnetic anisotropy and low damping at room temperature, making them promising for magnetic tunnel junction applications.

Contribution

It reports the realization of large PMA in Fe/MgAl2O4 heterostructures with properties comparable to Fe/MgO, including temperature stability and low damping, supported by experimental and theoretical analysis.

Findings

Large PMA energy (~1 MJ/m3) at room temperature

Weak temperature dependence of PMA and magnetization

Effective damping constant ~0.02 in 0.7 nm Fe layer

Abstract

We investigated 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 ~1 MJ/m3 at room temperature, comparable to that in ultrathin-Fe/MgO(001) heterostructures. Both the PMA energy and saturation magnetization show weak temperature dependence, ensuring wide working temperature in application. The effective magnetic damping constant of the 0.7 nm Fe layer was ~0.02 using time-resolved magneto-optical Kerr effect. This study demonstrates capability of the Fe/MgAl2O4 heterostructure for perpendicular magnetic tunnel junctions, as well as a good agreement with theoretical predictions.