Voltage-controlled magnetic anisotropy in antiferromagnetic L1_0-MnPt and MnPd thin films

摘要

The efficient electrical control of the magnetic states of antiferromagnets is one of the main focus in antiferromagnetic spintronics. In this work, the voltage-controlled magnetic anisotropy (VCMA) effect in two representative antiferromagnets L1_0-type MnPt and MnPd thin films has been investigated by employing first-principles calculations. Our results indicate that both of the MnPt and MnPd films show in-plane magnetic anisotropy and the magnetic easy axis points either along [1 0 0] or [1 1 0] direction depending on the film thickness. The applied electric field in the range of — 0.3 V/A and + 0.3 V/A (vacuum as dielectric) leads to the change of magnetocrystalline anisotropy of both films at the order of tens of uJ/m2. Especially, for MnPt film with thickness of two unit cells on Pt(0 0 1), it shows that the moderate electric field is able to switch the in-plane magnetic easy axis between [1 0 0] and [1 1 0] directions. For MnPd thin films, the VCMA effect shows generally linear dependence on the electric field and the VCMA coefficients are estimated in the range of 2.7 to 22.6 fJ/V/m. Our calculation results may stimulate future investigations on the VCMA effect of metallic antiferromagnetic films and pave the possible applications in memory device.