Modulation Of Substrate Morphology On Magnetic Film Properties And Application Studies

Magnetic components are continuously developing toward miniaturization and integration,and the regulation of magnetic anisotropy of soft magnetic thin film materials is important for the development of new magnetic components.In this thesis,we induce the in-plane uniaxial magnetic anisotropy by depositing permalloy（Ni Fe）films on periodic rippled sapphire substrates,investigate the factors affecting the uniaxial magnetic anisotropy of rippled films in combination with micromagnetic simulations and experiments,and design a planar Hall sensor based on rippled films.The main research works and results are as follows:Firstly,the effects of ripple wavelength,ripple height,and film thickness on the anisotropy of the film are investigated by means of micromagnetic simulations.The results show that the anisotropic field and the amplitude dispersion of the anisotropy of the rippled thin film show a negative correlation trend with the ripple wavelength and film thickness,and a positive correlation trend with the ripple height.Secondly,a batch of Ni Fe rippled films with different thicknesses were prepared by magnetron sputtering,and their static and dynamic magnetic properties were characterized.The measurement results of hysteresis lines show that the easy-axis coercivity of the rippled films increases with the increase of film thickness,and the hard-axis coercivity of the films does not change much with the increase of film thickness.The anisotropic field angle dispersion of different thickness films can be obtained from the remanence angle dependence curves of the films.The test results show that the films with 25 nm thickness exhibit the best uniformity of anisotropic field angle distribution,which will be used for the next step of sensor fabrication.The magnitude of the anisotropic field can be calculated by fitting the results to the thin film ferromagnetic resonance.The results show that the anisotropic field increases with film thickness when the film thickness is greater than 20 nm,and decreases with decreasing film thickness when the film thickness is less than 20 nm.Finally,a ripple film-based planar Hall sensor was designed.The micromagnetic simulation of the factors affecting the sensor performance was conducted first,and the results showed that the sensor sensitivity would decrease with the increase of ripple wavelength and film thickness,and increase with the increase of ripple height,and the measured magnetic field of the sensor would increase with the increase of ripple wavelength and film thickness,and decrease with the increase of ripple height.Then the planar Hall sensor was prepared and tested for performance with a sensitivity of S=45.20/Oe and a measured magnetic field of H_PHE=366Oe.