Magnetic and magneto-optical properties of MnPt3/Co multilayer

Abstract

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.

Strain Related Effects on the Structure and Magnetic and Magneto-Optical Properties of Epitaxial MnxPt1-xThin Films

“…Previously, some of ns have measured the polar Ken effect of bulk MnPts in an applied magnetic field of 8 T and found a maximum rotation of -0.551> at 1.2 eV 4). For MBE grown, (Ill) oriented MnPts thin films Kokuryu et al 5) found an intrinsic maximum Kerr rotation of -0.7° at 1.2 eV in contrast to our value of about -0.821> at 1.1 eV 6) for (001) oriented films. However, as is true for most cases of heteroepitaxial film growth, the lattice mismatch between the film and substrate materials cause considerable microstructural strain in films.…”

Size effects of optical and magneto-optical properties of epitaxial CrPt3 films

“…Only when the film thickness is reduced to a few atomic layers, surface anisotropy may dominate over the contribution of the bulk. 13 Therefore, it has been proposed to use multilayers with alternating thin films of the magneto-optically active medium and thin films of another metal which might be a paramagnet, such as Pt, 14 or an ordered material, such as Co. 15 Some of these attempts have been successful, others not, suggesting a need for a more systematic study of the various effects influencing the performance of these composite magneto-optical media. One group of effects is related to the growth of the films.…”