Growth And Magnetism Regulation Of Hexagonal Barium Ferrite Film Based On PLD Technology

With the development of communication technology,the integration and high frequency of microwave components have become the research central issue.As one of the core members of microwave components,microwave circulators are also developing rapidly.However,the conventional circulator needs additional permanent magnets,which led to an increase in the volume and weight,can not be integrated with other circuits.The development of film preparation technology provides an idea for the miniaturization and integration of circulators.At present,the performance of barium ferrite film is still insufficient,and it can’t meet the needs of circulators.Therefore,according to the development requirements of the circulator,this paper studies the growth of BaM film with high remanence,high magneto-crystalline anisotropy and the regulation of magnetic properties.（1）Based on the growth mechanism of the film,the influence of substrate temperature on the magnetic properties of BaM films was studied,and the deposition conditions for PLD growth of high remanence BaM films were optimized.Using PLD equipment,BaM films are grown on alumina substrates at different substrate temperatures.Then the crystal structure,microscopic morphology and magnetic properties of the film were characterized and analyzed.The crystal structure shows that the substrate temperature is a key factor affecting the orientation of the BaM film.The higher the substrate temperature,the higher the c-axis orientation of the film.The test results show that the substrate temperature has a significant effect on the crystallinity,surface morphology and magnetic properties of the film.（2）The remanence of the BaM film is improved by doping Al³⁺,and the influence of the doping amount of Al³⁺on the magnetic properties of the BaM film is studied.Ceramic samples doped with Al³⁺are prepared by solid-phase sintering,and then the corresponding Al-BaM thin film is grown using PLD technology.The test results show that Al³⁺doping can significantly increase the coercivity of BaM ceramics and films,but the saturation magnetization is drastically reduced.In addition,the doping of Al³⁺also increases the remanence ratio of the film.When the doping amount of Al³⁺is x=0.6,the remanence of the film is about 190 emu/cm³.This shows that doping a certain amount of Al³⁺can not only increase the magneto-crystalline anisotropy of the film,but also increase the remanence of the film.This work also reflects that PLD technology can obtain ion-doped films.the magnetic properties of the film can be adjusted by ion doping.This provides experience for the subsequent growth of other ion-doped films.（3）Based on the results of Al³⁺doping experiments,it shows that single ion doping can only achieve a single performance improvement,and cannot improve multiple performances.This paper attempts to use Al-Co-Zr ternary doping techniques to regulate the magnetic properties and BaM target film.On the basis of the previous experiment,fix the doping concentration of Al³⁺,and study the effect of Co-Zr doping concentration on the performance of BaM film.The test results found that PLD technology can grow multi-ion co-doped films,which is consistent with the performance of ceramics.The change of Co-Zr doping concentration can significantly control the saturation magnetization and coercivity of the BaM film.The concentration of Co-Zr increases from x=0 to x=0.15 and the saturation magnetization of the film increases from 180 to 260 emu/cm³.The remanence of the film reaches the maximum value of 132 emu/cm³ when x=0.1.This regulation result is contrary to the regulation mechanism of Al³⁺.Therefore,it is possible to comprehensively consider the doping concentration of Al³⁺and Co-Zr ions to obtain a high-performance BaM film.