Preparation And Properties Of FeGaB Magnetostrictive Films

Magnetostrictive materials have broad prospects in many fields such as underwater acoustic energy exchange magnetoacoustic antenna electromagnetic sensing.As a new type of magnetostrictive material,FEGAB has the advantages of large magnetostrictive coefficient and small coercoerity,and can combine with piezoelectric film to produce strong magnetoelectric coupling effect.And its low cost,good toughness,has a great potential in the application of practical devices.In the high frequency field,the introduction of Al₂O₃ layer can increase the resistivity of FeGaB film and reduce the eddy current loss,thus broadening the application range of FeGaB.In order to obtain FeGaB films with large magnetostrictive coefficient and small coercoerity and explore its application in the high frequency field,this paper studied the influence of process parameters in the preparation process on the properties of FeGaB films,and optimized the soft magnetic properties of FeGaB/Al₂O₃ multilayer magnetostrictive films.The magnetoelectric couplers were fabricated by MEMS micromachining technology to explore the high frequency application of FeGaB thin films.Firstly,the effects of different sputtering parameters on the properties of FeGaB films were investigated.The FeGaB films were prepared by magnetron co-sputtering method.The Fe Ga target was fixed on the DC target,and the B target was fixed on the AC target.The parameters such as sputtering power,sputtering time,sputtering gas flow rate and substrate temperature were changed and the experimental results were compared.The effects of these processing parameters on the composition,thickness,coercivity,magnetostrictive coefficient and other properties of FeGaB films were analyzed.The preparation process of FeGaB films with large magnetostrictive coefficient and low coercivity was determined.The results show that when the sputtering power of Fe Ga target is 40W,the sputtering power of B target is 40W,the argon gas flow is 20sccm,the sputtering time is 8h,and the substrate temperature is 60?,the coercivity of FeGaB film can be reduced to 2.1Oe,and the magnetostriction coefficient increases to about 64ppm.Secondly,parameters such as sputtering time were adjusted to control the thickness of FeGaB film and Al₂O₃ insulating layer,and Al₂O₃/FeGaB multilayer magnetostrictive film with a thickness of about 500nm was prepared.It is found that the FeGaB/Al₂O₃multilayer magnetostrictive films prepared by co-sputtering and alternate sputtering have excellent soft magnetic properties and large magnetostrictive coefficient,and the performance difference is small when the substrate is silicon wafer and AlN film.This lays a foundation for its application in magnetoelectric couplers.Finally,the FeGaB/AlN magnetoelectric coupler was fabricated by MEMS micromachining technology.Using an RF coil as the excitation source,the electromechanical resonance frequency of the device was measured at 5.1GHz,and the high frequency magneto-electric coupling performance was investigated.The simulation process of magneto-electric coupling effect using COMSOL Multiphysics simulation software is discussed.The FeGaB thin film prepared in this paper has a small coercoerity and a large magnetostrictive coefficient,and the magnetoelectric coupler shows a high resonance frequency,which provides the possibility for the further preparation of high frequency magnetoelectric coupling sensor with high magnetoelectric coupling coefficient and weak driving field...