High perpendicular anisotropy and magneto-optical activities in ordered Co3Pt alloy films

The origin of the large perpendicular magnetic anisotropy constant Ku of Co3Pt alloy thin films is discussed. The films deposited onto Al2O3(0001), Al2O3(112̄0), and MgO(111) substrates held at 230–450 °C during deposition exhibit Ku of the order of 107 erg/cm3 at room temperature. While the one dimensional long range order parameter S estimated by x-ray diffraction is very consistent with the development of the perpendicular magnetic anisotropy in the films deposited at 380–450 °C, very little evidence is found to suggest the correlation between S and Ku for the lower deposition temperature range (230–380 °C). To explain this, a short range ordering is suggested to be responsible for the origin of Ku, similar to the cases in Pt72Co28 alloys. The magneto-optical polar Kerr activity of ordered Co3Pt film is found to be enhanced for both θK and ηK in the photon energy range from 2 to 4 eV.