Temperature dependent coercivity and magnetization of light rare-earth Nd doped permalloy thin films

摘要

The temperature dependence of the magnetic properties of Ni_(80)Fe_(20) thin films with dilute Nd dopants has been studied. The effect of Nd dopants on the hysteresis loops of Nd-doped Ni_(80)Fe_(20) thin films is small at room temperature but large at low temperature. The measurements show an interesting temperature dependence of the coercivity with different concentrations of Nd impurities, which might be related to the film structure. The temperature dependence of the saturation magnetization for Nd-doped Ni_(80)Fe_(20) thin films is fitted by a theoretical expression of spin-wave excitation plus Stoner-type-like contribution, in which the spin-wave excitation plays a main role at low temperature. The spin-wave stiffness constant D evaluated from the fitting shows a strong doping concentration dependence.