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 degrees C have the CuPt type structure, whereas films grown onto (111) substrate at 500 degrees C and onto (100) substrate at 300 degrees C and 400 degrees C form in the PtCo ordered phase with AuCu structure. The film of the CuPt type exhibits a very large perpendicular magnetic anisotropy of 1.0x10(6) J/m(3), due to the layered structure along the film normal direction. The spectrum of Kerr rotation theta(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.