Preparation And Property Investigation Of Magnetic FeZrBCu Thin Films

The Fe-Zr-B-Cu nanocrystalline alloys(NANOPERM) had excellent soft magnetic properties, which exhibit a higher saturation magnetization than Fe-Cu-Nb-Si-B materials, moreover, the nanocrystalline BCC Fe phase ,formed as a result of a heat treatment, was simpler than theα-FeSi phase occurring in Fe-Cu-Nb-Si-B materials. As a result, they had been extensively studied in recent years.The FeZrBCu alloy targets of magnetron sputtering were manufactured by powder metallurgy. The composition of the targets after sintering have no distinct difference with the designed composition, and the density of the targets increase to some extent after sintering; The density and hardness of the targets increase when the sintering temperature was elevated and the holding time was prolonged. The hardness of the target continuously increase as the sputtering time increasing.The FeZrBCu thin films were prepared by DC magnetron sputtering, XRD result indicates that the as-deposited films were amorphous. The surface topography,surface roughness of the films prepared at different sputtering parameters were observed by scanning electron microscope(SEM) and surface roughness testing instrument, respectively. The chemical compositions were analyzed by energy dispersive spectroscopy. The square resistance of the films were measured by four points method. The saturation magnetization,coercivity,retentivity and hysteresis loop of the samples were measured by vibrating sample magnetometer. The effect of sputtering parameters, such as sputtering power,argon gas pressure,distance between substrate to target,initial vacuum,negative bias voltage, and so on, on the depositional rate,surface topography,surface roughness,electrical resistivity and magnetic properties were studied. The composition and temperature dependence of the electrical resistivity and magnetic properties were also discussed. The amorphous FeZrBCu thin ribbons were prepared by single roller melt-spinning, the magnetic properties of which were also compared with the films of same composition prepared by magnetron sputtering.The experimental results show that the sputtering parameters have great effect on the depositional rate,surface topography,surface roughness,electrical resistivity and magnetic properties of the films. The depositional rate increase firstly and decrease when the sputteringpower,argon gas pressure,negative bias voltage increase. The depositional rate decrease as the distance between substrate to target increase. As the initial vacuum increase the depositional rate decrease firstly and increase, but the quality of the film deteriorate. The depositional rate increase to some extent when negative bias voltage added. High surface quality film can be obtained when the sputtering power was 100W,argon gas pressure was 1.0Pa,substrate to target distance was 6.5cm,initial vacuum was 1.5×10-3Pa and negative bias voltage was 120V. The electrical resistivity of the film decrease firstly and increase when the sputtering power,substrate to target distance,negative bias voltage increase. The electrical resistivity increase as the argon gas pressure,initial vacuum,Zr and B content increase. The electrical resistivity of the film can be reduced when negative bias voltage added. As the annealing temperature increase the electrical resistivity decrease drastically.The effect of sputtering parameters on the magnetic properties of the film as follows: The saturation magnetization and coercivity increase as sputtering power increase, while decrease as argon gas pressure increase. The saturation magnetization and coercivity increase firstly and decrease as substrate to target distance increase. As the initial vacuum increase, the saturation magnetization increase firstly and decrease while the coercivity decrease. As the negative bias voltage increase, the saturation magnetization decrease firstly and increase, the coercivity almost unchanged when negative bias voltage below 120V and give a drastic increase when negative bias voltage exceed 120V. The saturation magnetization decrease as the Zr and B content increase. The saturation magnetization increase as the annealing temperature increase and the coercivity has a maximum value when the annealing temperature was 573K. The saturation magnetization of FeZrBCu thin film prepared by magnetron sputtering was higher than that of FeZrBCu thin ribbon prepared by single roller melt-spinning. The coercivity of Fe89Zr7B2Cu2 thin ribbon prepared by single roller melt-spinning was smaller than that of prepared by magnetron sputtering, and the retentivity ratio has no distinct difference; The coercivity of Fe91Zr4B3Cu2 thin ribbon prepared by single roller melt-spinning and magnetron sputtering were in the same value, but the retentivity ratio was much larger than the later.