A Comprehensive Study of Sign Change in Electric Field Control Perpendicular Magnetic Anisotropy Energy at Fe/MgO Interface: First Principles Calculation

Electric field (EF) control on magnetic anisotropy energy (MAE) in the system which contains Fe/MgO interface with Cr underlayer was performed by means of first-principles electronic structure calculations. An opposite sign in EF coefficient (y) was observed by introducing Fe/Cr intermixing. This intermixing leads to a substantial rearrangement in the electronic structure due to proximity effects of Fe and Cr. The origin of such an opposite sign in y was discussed along with the modulation of occupied and unoccupied d-band near the Fermi level. By introducing a strain effect, the enhancements of MAE and y were achieved with the maximum absolute values, 2.43 mJ/m
²
and 170 fJ/Vm, respectively. The present result provides a new possible degree of freedom for the EF control in MAE as the underlayer configuration.