Perpendicular magnetic anisotropy caused by interfacial hybridization via enhanced orbital moment in Co/Pt multilayers: Magnetic circular x-ray dichroism study

Magnetic circular x-ray dichroism (MCXD) measurements-at the Co L-2,L-3 and M-2,M-3 core edges reveal a strongly enhanced perpendicular Co orbital moment (m(orb)) in Co/Pt multilayers which show perpendicular magnetic anisotropy (PMA). MCXD signals at the Pt N-6,N-7 and O-2,O-3 edges, arising from Pt 5d-Co 3d hybridization, persist for the thinnest Co layer. The hybridization is shown to be localized at the Co/Pt interface and to cause the m(orb) enhancement which drives PMA. Unambiguous evidence for a transition from fee to hcp Co is presented and m(orb) of bulk fee Co has been determined to be 0.11 mu(B) for the first time.