Temperature-Dependent Magnetic Damping Constant of Fe2Co Films Doped by Rare-Earth Yb

Abstract

The temperature-dependent magnetic properties are investigated in amorphous (Fe2Co)[Formula: see text]Ybx ([Formula: see text], 0.64) thin films with in-plane uniaxial anisotropy. The decreases of saturation magnetization and easy axis coercivity with increasing temperature were observed and quite well explained by the Bloch’s law of [Formula: see text] dependence based on three-dimensional (3D) spin wave excitations and the thermally activated domain wall motion model of [Formula: see text] dependence, respectively. The decrease of in-plane uniaxial anisotropy constant is also observed and can be quite well fitted at temperature below 300[Formula: see text]K. The magnetic damping constant, which was deduced from the angular dependent ferromagnetic resonance spectra, shows a minima over the temperature range 100–435[Formula: see text]K, just like the previous results from 3D-transition metals based on Kamberský’s torque-correlation model. However, a positive correlation between damping and the in-plane uniaxial anisotropy constant was obtained with a clear deviation from the linear relationship. This deviation indicates that temperature-dependent damping and anisotropy may have different origins instead of the common source of the temperature-dependent spin-orbital coupling strength.