Manipulating the magnetic anisotropy of 3d transition-metal films on Cu(001) and their alloys on Rh(001) by electric field

• The mechanism of electric field effects on magnetic anisotropy is proposed.
• A large effect relies on a Fermi energy close to the cross point of two key bands.
• Using a Rh or Pd substrate will weaken the electric field effect for Fe monolayer.
• Switch of the magnetization direction can be achieved in FeCo alloy film on Rh(001).

The mechanism of electric field (EF) effects on the magnetocrystalline anisotropy (MCA) in metallic films is investigated by first-principles calculations. Start with a simple system of Fe, Co and Ni monolayer on Cu(001) substrate, we show that the key factor for a large EF-induced MCA modification is that the energy bands cross of d3z2−r2d3z2−r2 and dyzdyz (or dxzdxz and dxydxy) is close to the Fermi level. In order to enhance the MCA modification by EF, 4d metal substrates (Rh, Pd) are also discussed. In particular, we find that the magnetization direction can be switched from out-of-plane to in-plane by a small EF for Fe1–xCox alloy films on Rh(001) substrate with x=0.5.