Perpendicular magnetic anisotropy and magneto-optical Kerr spectra of MBE-grown PtCo alloy films

Pt₅₀Co₅₀ alloy films have been grown by MBE method onto heated MgO(100) and (111) substrates. It is found that films grown on a (111) substrate at 300°C have the CuPt type structure, whereas films grown onto (111) substrate at 500°C and onto (100) substrate at 300°C and 400°C form in the PtCo ordered phase with AuCu structure. The film of the CuPt type exhibits a very large perpendicular magnetic anisotropy of 1.0×10⁶ J/m³ , due to the layered structure along the film normal direction. The spectrum of Kerr rotation θ_k of the film with CuPt structure is considerably different from that of AuCu structure, not exhibiting a maximum around 4.0 eV but showing a peak at 1.4 eV