We have investigated the electric field (EF) effect on the magnetic anisotropy energy (MAE) in the thin films MgO/M/Fe/Au(001) and MgO/Fe/M(001) (M = Pd, Pt, and Au) by means of first-principles density-functional calculations. We find that the MAE varies linearly with the EF and investigate the change in slope of the MAE as a function of the EF as the buffer layer is changed. We find that a single monatomic buffer layer may be useful for devices that use EF-modified MAE. We simulate the critical EF for easy-axis rotation and discuss interface effects of Mg/Fe and Fe/Au on MAE.

Abstract. Electric-field (EF) effects have been studied on magnetic anisotropy in the metallic surfaces Pt/Fe/Pt(001) and Pd/Fe/Pd(001) by means of the first-principles electronic structure calculation which employs the generalized gradient approximation. The variation of anisotropy energy with respect to the EF is found to be opposite to each other. The modulus rate of the variation is larger by a few factors in the Pt substrate than in the Pd one. These results agree qualitatively well with the available experimental data. The electronic structures are presented and the origins in EF effects are discussed along a line of the second perturbative fashion.

We have investigated the electric field (EF) effect on the magnetic anisotropy energy (MAE) in thin films MgO/Fe/M(001) (M = Au and Pt) by means of first-principles density-functional calculations. The EF dependence of the MAE is enhanced significantly in the film with the Pt substrate compared to that with the Au substrate. This enhancement is attributed to the EF-induced hybridization between Fe 3d- and Pt 5d-orbitals. This implies that the Pt layer stacked on the magnetic layer strengthens the sensitivity of devices for bias-voltage-induced magnetic control.

We investigated the effect of an electric field on the interface magnetic anisotropy of a thin MgO/Fe/MgO layer using density functional theory. The perpendicular magnetic anisotropy energy (MAE) increases not only under electron depletion but also under some electron accumulation conditions, showing a strong correlation with the number of electrons on the interface Fe atom. The reverse variation in the MAE under the electric field is ascribed to novel features on the charged interface, such as electron leakage. We discuss the origin of the variation in terms of the electronic structures.

The magnetic anisotropy of monatomic Fe films on Pd(001) with or without a Pd overlayer was investigated from the standpoint of interface atomic structures. Quantitative analysis included low-energy electron diffraction and x-ray magnetic circular dichroism (XMCD) experiments, and first-principles calculations were also performed on monatomic Fe and Pd/Fe systems. It was revealed that Fe atoms intermix with the Pd substrate at room temperature. A spin reorientation transition occurs at a critical Fe thickness of 1.2 monolayers (ML) in Fe/Pd(001), while in-plane magnetic anisotropy is persistent in Pd/Fe/Pd(001) throughout the entire sample. The Fe 3d spin and orbital magnetic moments for both systems are strongly enhanced near 1 ML Fe thickness, as compared to those of the bulk iron crystal. In addition, an induced magnetic moment in interfacial Pd atoms was observed by XMCD at the Pd M 2,3 core absorption edges. It was concluded that the L1 0 -like tetragonally distorted interface atomic structure in monatomic Fe/Pd(001) induces the perpendicular magnetic anisotropy.