Surface magnetic field distribution simulation of permanent magnet thin film in micromechanical gyro
In the micromachined gyroscope based on the tunneling magnetoresistance effect,the generation and distribution of magnetic field is an important factor to determine the performance of the device.In this paper,NdFeB permanent magnet film is used as the magnetic field source,and the surface magnetic field of NdFeB permanent magnet film is systematically analyzed by Comsol Multiphysics software based on finite element method.The uniformity of the magnetic field distribution on the surface of the film under different film thicknesses and the change rate of the magnetic field component in the direction of the tunnel reluctance sensitive axis are studied.It is found that with the increase of film thickness,the surface magnetic field and magnetic field change rate of the film also increase.When the film thickness is 20 μm,the magnetic field change rate generated by the film can reach 0.43 mT/μm.Considering that the film array can effectively suppress the weakening of the adhesion between the film and the substrate caused by the excessive thickness of the film,the surface magnetic field distribution of the one-dimensional array of NdFeB permanent magnet thick film is studied by changing the design parameters.It is found that when the thickness and width of the array unit increase,the magnetic field intensity and magnetic field change rate of the array will also increase,while the increase of the spacing will lead to the decrease of the surface magnetic field and magnetic field change rate of the film array.
surface magnetic field distributionthin film arraymagnetic field change rate
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