Transmission Electron Microscopy Study of CoPt(001) and FePt(001) Films Formed from Epitaxial Co/Pt and Fe/Pt Multilayers

Transmission electron microscopy was performed on epitaxial Fe/Pt and Co/Pt [001] oriented multilayers that were sputter deposited onto single crystal [001] MgO. Films were examined as-deposited and after annealing in vacuum. Before annealing, the films had a magnetic easy axis in the plane while after annealing the easy axis was out of the plane. Perpendicular anisotropies of 8×l06 erg/cm3 and 1.9×107 erg/cm3 were measured for the Fe/Pt and Co/Pt post-annealed films. Large magneto-optic Kerr rotations were also measured, 0.6° and 0.4° for the Fe/Pt and Co/Pt annealed films, respectively. Changes in the magnetic properties were a direct result of the transformation of the multilayer into c axis oriented FePt and CoPt intermetallic compounds upon annealing.