Structure And Magnetic Properties Of Nd-doped Nano-magnetic FeCo Thin Films

High frequency soft magnetic thin films used in electromagnetic devices are increasingly becoming a very active research field in demand with miniaturization and high frequency in electromagnetic devices.The theoretical and experimental results show that the Fe-Co based soft magnetic thin film is one of the best materials in high frequency application field.The high frequency soft magnetic properties of Co-based amorphous thin films can be improved by the rare-earth elements doping.In this work,a series of nano-magnetic thin films of Ta/FeCo-Nd/Ta were prepared by RF magnetron sputtering with different power of Nd and substrate temperature.The structure and the surface profile of the samples were characterized by X-ray Diffraction(XRD) and Atomic Force Microscope(AFM),respectively.The magnetic properties and the domain structure of samples were systematically studied by vibrating sample magnetometer(VSM) and Magnetic Force Microscope(MFM), respectively.Meanwhile,the high-frequency characteristics of complex permeability were obtained by using the shorted microstrip transmission-line perturbation method. The main contents are briefly introduced as follows:错误!未找到引用源。The thin films prepared with substrate temperature at 300℃have none in-plane magnetic anisotropy.The same results were obtained on annealed films.With increasing of Nd content,the saturation magnetization decreases and the coercivity increases.The resonance frequency of 1.5 GHz of Nd₂₀(FeCo)₈₀ sample is obtained because of the rotatable magnetic anisotropy.错误!未找到引用源。For the thin films prepared with no heating substrate:The structure and magnetic properties of FeCoNd films with Nd concentration and annealing temperature with magnetic field under vacuum were investigated.The as deposited films are amorphous.The size of the FeCo and FeCoNd nano-crystallites increases with the increasing of annealing temperature.The results from vibrating sample magnetometer measurement revealed that the saturation magnetization decreases with the increasing of Nd concentration. The Nd₁₃(FeCo)₈₇ film shows non in-plane magnetic anisotropy,due to the existence of perpendicular magnetic anisotropy,which is confirmed by the stripe domain obtained by MFM.An in plane magnetic anisotropic property of FeCoNd films was obtained by vacuum annealing with magnetic field when the Nd concentration higher than 13%. The Ta/Nd₂₀(FeCo)₈₀/Ta sample shows the coercivity of 2.5Oe and 1.7Oe at easy and hard axes respectively and anisotropic field of 102.6Oe,indicating the potential application in high-frequency fields.