Perpendicular Magnetic Anisotropy Caused by Interfacial Hybridization via Enhanced Orbital Moment in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>Co</mml:mi><mml:mi>/</mml:mi><mml:mi>Pt</mml:mi></mml:math>Multilayers: Magnetic Circular X-Ray Dichroism Study

Abstract

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