Magnetic Regulation Of Metal Magnetic Thin Films In GHz Band

Microwave magnetic devices require a wide range of magnetic permeability and resonance frequencies of magnetic films in the GHz band,and good thermal stability.It is difficult to realize the large-scale control for resonant frequency and magnetic permeability of magnetic thin films.Based on the LLG equation and Kittel formula and bianisotropy model,the CoFeB and Co Z magnetic thin films were researched in this paper.The uniaxial anisotropy of the CoFeB film is controlled by the oblique sputtering.The resonant frequency is regulated from the S-band to the X-band in wide range.The dependence of temperature and magnetic parameters of the thin films were verified by using a high temperature test apparatus.The optical resonant frequency of Co Zr thin film is controlled by regulated the exchange effect in the stripe domain structure.The main innovative results are as follows:1.The high frequency magnetic properties of CoFeB thin films are controlled by oblique sputtered to induced anisotropy.It is realized continuous modification of the resonance frequency of CoFeB thin films in GHz range.With the increase of the oblique sputtering angle,the uniaxial anisotropy field in the film can increase from 50.1 Oe to 608.7 Oe.,and the resonance frequency increases from 2.83 GHz to 9.71 GHz.2.A short-circuit microstrip line probe is designed for the testing of the permeability of the thin film material at high temperature.The probe can measure the permeability spectrum from room temperature to 200 °C in the range of 100 MHz-7 GHz.3.The high thermal annealing and high temperature magnetic permeability spectroscopy show that the CoFeB soft magnetic film still has high thermal stability.With the temperature increases from room temperature to 200 °C,the anisotropy field of Co Zr thin films decreases from 77 Oe to 58 Oe,and the resonant frequency decreases from 3.01 GHz to 2.71 GHz,and it still shows good high frequency magnetic property at high temperature.4.The size of the magnetic domain structure in the Co Zr stripe domain film is changed by changing the geometrical parameters of the film,which regulates the exchange field between adjacent magnetic domains in the film and realizes the control of the optical resonant frequency from 3.5 GHz to 5.1 GHz.