Preparation And Study Of The High Frequency Magnetic Properties Of Patterned FeCoBSi Thin Film

With the development of information technology, microwave material have been widely used in various fields of society, and an inevitable development trend of “high frequency”, “broadband” is formed in the magnetic material. In this aspect, the ferromagnetic metal film has received more and more attention, because of its thin thickness and high permeability. But there are two major defects in this material. On the one hand, the surface electrical conductivity is too high which is easy to lead an independence mismatch, thus affecting the performance in microwave frequency. On the other hand, the controllability of ferromagnetic thin film is very poor and it’s difficult to adjust the magnetic parameter by coating technology. In emerging technologies, the patterning design can cut surface current and reduce the conductivity, the different patterns and interlayer coupling is expected to achieve magnetic adjustable. It is the key technology to solve the “high frequency”, “broadband” and “high resistivity” problems of ferromagnetic thin film. Based on it, we take the FeCoBSi ferromagnetic thin film as the research object and launched a research on the ferromagnetic thin film pattern optimization design, the preparation experiment and the study of magnetic properties. Be aimed to effectively regulate its resonance frequency and high frequency permeability.In this paper, we firstly prepared a series of FeCoBSi thin film with different thickness by magnetron sputtering method, and researched its static and dynamic magnetic properties. The result shows that the magnetic field can not only induce in-plane uniaxial anisotropy in the film,but also restrict the in-plane anisotropy field in a very small variation range, which make the resonance frequency change slightly with the film thickness. In order to achieve the purpose of adjusting the resonance frequency in a large scale range, the simulation design of micro scale patterned ferromagnetic thin film was carried out by using the open source micromagnetic simulation software OOMMF. In the simulation of stripe pattern, we found that the stripe unit with shape anisotropy could observably increase the in-plain anisotropy field of the film. By changing the stripe width, magnetic phase ratio and the film thickness, all can achieve a large amplitude regulation on its permeability and resonance frequency. However, due to the decrease of magnetic phase ratio, the saturation magnetization and the magnetic permeability have suffered a significant loss. The experiment result of the stripe patterned FeCoBSi thin film has verified the correctness of simulation. In order to achieve the purpose of “broadband”, the simulation design of the combined-stripe pattern is carried out. The simulation result shows that an obvious multi-peak resonance phenomenon can be observed. And the resonance peaks are excited by the different width of stripes, respectively. By controlling the number ratio of stripes in graphic element, we can adjust the value of peaks. The bigger the number ratio, the stronger the peak. The resonance band broadening phenomenon caused by the superposition of the resonance peaks was also observed in the experimental study on the combined-stripe patterned FeCo BSi thin film. In a word, we can achieve a signification adjustment of the resonance frequency of ferromagnetic thin film and broden the resonance frequency band by patterning design.