Magneto-Optical Spectra and Magnetic Anisotropy of MBE-Grown CoPt Alloy Films with L1<sub>0</sub> and L1<sub>1</sub> Ordered Structure(s)

Abstract

Co50Pt50 alloy films were grown by the molecular beam epitaxy (MBE) method onto MgO(111) or (001) substrates at temperatures in the range of 40 to 500 °C. X-ray diffraction measurement demonstrated that the films grown onto the (111) substrates at 300 °C had L11 (CuPt type) ordered structure, whereas those grown onto the (111) substrates at 500 °C and onto the (001) substrates at 300 °C formed L10 (CuAu type) ordered structures. The (111) oriented L11 and the (001) oriented L10 CoPt alloy films showed large perpendicular magnetic anisotropies of 1.75 × 106 J/m3 and 1.8 × 106 J/m3, respectively. The magneto-optical Kerr spectra for the (001) and (111) oriented L10 CoPt alloy films are similar. The (111) oriented L11 CoPt film showed Kerr spectra quite different from those of the L10 CoPt films. The θK did not show a peak in the high energy region.