Highly ordered MnPt3 alloy film was grown by molecular-beam epitaxy (MBE) at a temperature of 300 °C. The MnPt3 film exhibits a large Kerr rotation, which reaches a maximum value of −0.7° at 1.24 eV. MnPt3(2 nm)/Co(0.6 nm) multilayers were also grown by MBE method onto MgO(111) substrates at a temperature of 300 °C. It was verified by the observation of the reflection high-energy electron diffraction patterns that Co and MnPt3 layers in the film were grown epitaxially on MgO(111). The appearance of superlattice line due to Cu3Au structure in x-ray-diffraction patterns confirmed the formation of the ordered phase in the MnPt3 layer. The hysteresis loops for in-plane and film normal directions became close to each other, which implies that the perpendicular magnetic anisotropy was induced through the multilayered structure. The Kerr spectrum of the MnPt3/Co multilayer have a negative peak of −0.26° around 1.4 eV. This value is fairly smaller in magnitude compared to the one estimated by the effective reflectivity method using the optical and the magneto-optical constants for Co and MnPt3 alloy.

MnPt/Co multilayer films were grown by the molecular-beam epitaxy (MBE) onto MgO( Ill) substrates at a temperature of 300 'c. Small angle XRD measurements demonstrated that the samples had multilayered structure with sharp MnPt/Co interfaces. The appearance of superlattice lines due to CU,Au structure confirmed a partial formation of the ordered phase in the MnPt, layers. The [MnPt,( 1.9 nm)/Co(O.4 nm)J lO multUayer showed a preferential magnetization perpendicular to the film plane and a 100% perpendicular remanence. The Ken spectrum of the multilayer had a negative peak of -0.24 deg around 1.4 eV and showed a enhancement in the high energy region. This result implies the existence of the ordered phase in the MnPt, layer and alloying layer of Co and Pt at the MnPt/Co interface.

-The magnetic and magneto-optical properties of ordered Mnl_xFexPt3 alloy (~x::::;O.4S) films were investigated. The films were prepared by annealing Mn 1-xFexlPt multilayers at a temperature of 800 0 C. The MnPt3 alloy films was found to exhibit very large magneto-optical Kerr rotation, which reaches a maximum value of -1.2 deg at 1.24 eV. From the spectra of the off-diagonal component of conductivity tensor together with the diagonal component of dielectric tensor, it is suggested that the large Kerr rotation is due not to the plasma resonance but to strong interband transitions. MnPt3/Co multilayer films were also prepared by MBE, and found to exhibit perpendicular magnetic anisotropy induced by the multilayered structure.