抄録
Pt50Co50 alloy films were grown by the MBE method on MgO(l00) and (111) substrates at temperatures between 300 and 500°C. The crystal structure of the films grown on the (100) substrate was a PtCo ordered phase of AuCu type. The crystal structure of the films grown on the (111) substrate depended on the growth temperature. While the structure of the films grown at temperatures above 500°C was a PtCo ordered phase, the structure of the film grown at 300°C was a rhombohedral system with a layered structure in the [111] direction. The film exhibited a very large perpendicular magnetic anisotropy of 1.0×106 J/m3, due to the layered structure with a bilayer thickness of 0.43 nm. The spectra of the Kerr rotation θk of the ordered PtCo alloy films showed a peak at 4.0 eV. Anisotropy of the spectrum depending on the film orientation was observed. The spectrum of a film with a rhombohedral system differed considerably from that of a film with an ordered phase, which did not exhibit a maximum around 4.0 eV, but had a peak at 1.4 eV.
