The perpendicular magnetic anisotropy of CoPt/Au multilayer films

We have studied the magnetic properties of Au (2 nm)/Co50Pt50 (3 nm)/Au (2 nm) multilayer films prepared on amorphous Al2O3/Si and (0 0 1) MgO substrates. The as-deposited films on both substrates are magnetically soft with an FCC structure and exhibit a perpendicular anisotropy. After annealing at 500 °C, the sample on the Al2O3/Si substrate has become magnetically isotropic but the sample on the MgO substrate still has perpendicular anisotropy with FCT structure. This film deposited on the MgO substrate did not show a strong perpendicular anisotropy due to the diffusion of the Au and the (1 1 1) nucleation of initial Au layer. We can obtain a perpendicular anisotropy in the multilayer films without an initial Au layer on a (0 0 1) MgO substrate. After annealing at 400 °C, these films have L10 phase with (0 0 1) texture and strong perpendicular anisotropy.