Gigantic transverse x-ray magnetic circular dichroism in ultrathin Co in Au/Co/Au(001)

摘要

Transverse-geometry x-ray magnetic circular dichroism (TXMCD) measurements on Au/Co-staircase/Au(001) reveal the orbital origin of intrinsic in-plane magnetic anisotropy. A gigantic TXMCD was successfully observed at the Co L_(3,2) edges for Co thickness (t_(Co)) in the 2-monolayer regime. A TXMCD-sum-rule analysis shows a remarkable enhancement of an orbital-moment anisotropy (Δm_(orb)) and of an in-plane magnetic dipole moment (m_T~‖).Both Δm_(orb) and m_T~‖ exhibit close similarity in tCo dependence, reflecting the in-plane magnetic anisotropy. These observations evidence that extremely strong, intrinsic, in-plane magnetic anisotropy originates from the anisotropic orbital part of the wave function, dominating the dipole-dipole-interaction-derived, extrinsic, in-plane magnetic anisotropy.