Research On Static And Dynamic Magnetic Control Of FeNi Patterned Film

With the continuous development of science and technology,the performance of various electronic products and the corresponding communication technology continue to improve and progress,the production and life become more and more convenient.It requires the performance of electronic products must be further improved,that is,while the product is miniaturized,it meets the requirements of high-frequency communication,integrated functions,stability and low energy consumption.All requirements set a new condition on corresponding raw materials.This is especially true in the magnetic materials industry.Soft magnetic materials are widely used in high-frequency fields due to their high initial permeability and low coercivity.Soft magnetic metal and soft ferrite are widely used in soft magnetic material system.Compared with soft ferrite materials,soft magnetic metals have higher saturation magnetization and processability,which is more conducive to increasing sensitivity,reducing the size of the device,and integrating processing.In addition,the working frequency of magnetic materials is mainly determined by the equivalent magnetic anisotropy of the system.The effective magnetic anisotropy determines that the magnetic anisotropy can be adjusted in order to increase the operating frequ ency.In view of these two reasons,the anisotropic regulation of high-frequency metal soft magnetic thin films has attracted widespread attention from industry and academia.People mainly use magnetic crystal anisotropy and stress anisotropy to adjust the in-plane magnetic anisotropy of the system,but this requires materials have strong magnetic crystal anisotropy or stress anisotropy,which is not universal.While the shape anisotropy can be adjusted in all materials,this subject uses the basic starting point of shape anisotropy,adjusting and combining with the change of the magnetic interlayer coupling strength in the magnetic multilayer film system to finally regulate the performance of the material in the filed of high-frequency electromagnetic.In view of the above considerations,this subject mainly takes FeNi with weak magnetic crystal anisotropy as the research object,and uses magnetron sputtering and photolithography to grow multilayer FeNi alloy soft magnetic films on different substrates to change the surface morphology of the films and graphical shapes,to achieve shape anisotropy regulation and interlayer coupling strength changes,and finally regulate the high-frequency magnetic properties of soft magnetic thin films.This thesis mainly studies the following two parts:The main research content of this subject is to use magnetron sputtering and lithography techniques to grow multiple layers of Fe-based alloy soft magnetic thin films on different substrates,and the magnetic anisotropy and interlayer coupling were changed by changing the surface morphology of the thin film and preparing a patterned cell structure.The magnetic anisotropy and interlayer coupling can further adjust the high-frequency magnetic properties of the soft magnetic film.This paper mainly studies the following two parts:（1）Prepare single-layer FeNi thin film,FeCo thin film and FeNi/Ta/FeNi sandwich thin film,and study their high frequency magnetic properties.Triangular corrugated nanopatterns were prepared on a single-sided polished 5 mm*5 mm Al₂O₃ substrate surface by high temperature annealing,and single-layer FeNi films,FeCo films,and FeNi films were grown on the patterned substrate surface by magnetron sputtering.Ta/FeNi sandwich film,and the thickness of the Ta layer is changed by an integer thickness between 0-5 nm.The composition,static magnetism and dynamic magnetism of the thin films were characterized by X-Ray Diffraction,Vibrating Sample Magnetometer and vector network analyzer.The results show that the high frequency magnetic?_r of the FeNi thin film is larger than that of the FeCo thin film.Therefore,further research on the FeNi/Ta/FeNi sandwich thin film reveals that the maximum?_r reaches 3.96GHz when the Ta layer is 4 nm.（2）Preparation of double-period（FeNi/Ta）₂ films and research it’s high frequency magnetic properties.A triangular corrugated substrate was prepared by high temperature annealing,and then a dual-cycle（FeNi/Ta）₂ thin film was prepared by magnetron sputtering,and a regular array of 15μm width and spaced lines was prepared on the sample surface by means of photolithography.To achieve the superposition of nano patterns and micro lines.The surface patterns of substrates and samples were characterized by Atomic Force Microscope,step profiler,Scanning Electron Microscope,and their static and dynamic magnetic properties were characterized by Vibrating Sample Magnetometer and vector network analyzer.It was found that compared to the?_r of the two types of samples with only nano-patterns and only micro-line,the maximum?_r of the superimposed sample reached 4.5GHz,the sample with only micro-line was 0.8 GHz,and the sample with only nano-pattern was 3.3 GHz.Adjustment outside the frequency range.