In-plane magnetic anisotropy of ultrathin bcc(110) transition-metal films

The in-plane and off-plane magnetic anisotropy energies (MAE) of bcc (110) transition-metal monolayers and bilayers are determined by calculating the spin-orbit coupling effects, the spin-density distribution, and the electronic spectrum self-consistently for each magnetization direction. The MAE shows a complicated behavior as a function of d-band filling and is very sensitive to film thickness. Alternations of the easy and hard axes between the off-plane and different in-plane directions are identified as well as transitions between uniaxial and multiaxial MAE surfaces. Remarkably, the in-plane anisotropy is often of the same order of magnitude as the off-plane anisotropy.