厚度对Ni_(25)Fe_(75)-ZnO颗粒膜阻尼因子和软磁特性的影响

The influence of film thickness on damping factor and soft magnetic properties of Ni_(25)Fe_(75)-ZnO granular films

采用磁控溅射制备了(Ni_(25)Fe_(75))-ZnO颗粒膜,研究了其高频动态磁性与薄膜厚度的关系,用Landau-Lifshitz-Gilbert方程计算出阻尼因子,并用一个幂函数拟合与外场的关系曲线。实验结果和拟合结果表明,动态磁化时有效阻尼系数αeff和内禀阻尼系数αint均随着样品厚度减小而增大。αint和αeff变化的物理起源应该与微结构的不均匀性、薄膜与衬底之间的界面效应和薄膜中的混杂物有关。

(Ni25Fe75)ZnO granular films with various thicknesses were deposited by magnetron co-sputteringmethod.The effective damping factor was calculated by Landau-Lifshitz-Gilbert equation.The dependence of theeffective damping factor on the external fields was fitted with a power function.The measurement and fitting resultsshow that both the effective and the intrinsic damping coefficients in the magnetization dynamics gradually increasewith the decrease of the film thickness t.It suggested that the physical origins of the variation forαnt andαeff should berelated to the microstructure inhomogeneity,the interface effect between the film and the substrate and the impurity inthe films.