Magnetic and structural properties of Fe/Cu multilayers

Abstract

Fe/Cu multilayers with Fe and Cu layers of equal thicknesses were grown by high-vacuum evaporation on Si(1 1 1) substrates at room temperature. The crystal orientation, the thickness of the elemental layers and the interplanar distances were analysed by both low- and high-angle X-ray diffraction in the θ–2θ configuration. The magnetic properties of Fe/Cu multilayers were studied by both a static and a dynamic technique, namely surface magneto-optical Kerr effect (SMOKE) and Brillouin light scattering (BLS). Longitudinal SMOKE cycles permitted us to determine the orientation of the easy axis of the magnetization and to put in evidence an appreciable in-plane magnetic anisotropy in multilayers with low periodicity and highly coherent structure. Polar loops were then used to determine the out-of-plane anisotropy fields, showing that both first- and second-order contributions are to be considered in order to reproduce the hysteresis cycle. BLS was then exploited to detect thermaly excited spin waves through inelastic scattering of light. The out-of-plane anisotropy fields evaluated by this high-frequency dynamic technique compare fairly well with the first-order values obtained by analysis of polar SMOKE hysteresis cycles.