Perpendicular exchange bias of (Pt/Co)_n/FeMn multilayers

(Pt/Co)_n/FeMn multilayers with perpendicular anisotropy (PA) were prepared by magnetron sputtering with Pt as the buffer layer and the capping layer. The dependence of perpendicular exchange bias (PEB), H_ex, on the thickness of the FeMn anfiferromagnet (AFM) layer is similar to that of in-plane exchange bias. The value of H_ex for the (Pt/Co)₃/FeMn multilayer reaches 22.3 kA/m. A thin Pt spacer was inserted between the Co/FeMn interface to enhance PEB. The PEB reaches the largest at 39.8 kA/m when the thickness of the Pt spacer is 0.4 nm.