Ferromagnetic resonance in Co - Nb/Pd multilayers

Abstract

multilayers were prepared by the rf sputtering method. The polarization of Pd layers and the interlayer coupling through Pd layers were studied via magnetic and ferromagnetic resonance measurements. Magnetic measurement shows that the saturation magnetization of Co - Nb/Pd multilayers oscillates periodically when the Pd layer thickness increases, which is caused by the oscillatory polarization of the Pd layers. The spin-wave excitation indicates that a ferromagnetic interlayer coupling can exist until the thickness of the Pd layers is about 7 nm. An oscillatory variation between 2.00 and 2.12 of the effective g-factor, , with the thickness of Pd layers was observed for the first time. The oscillatory period of is about 1 nm. A similar oscillatory behaviour of the effective anisotropy, , was also obtained. This oscillatory behaviour of and was interpreted in terms of a model of two exchange-coupled sublattices: one sublattice is that of the Co - Nb magnetic layers, and the other is that of the polarized Pd layers. This model indicates that the oscillatory behaviour of and mainly originates from the oscillation of the polarization of the Pd layers.