| Anisotropic magnetoresistance(AMR) sensors are widely used due to their low power consumption,high sensitivity,small size,low noise,high reliability and strong resistance to harsh environments.Permalloy(NiFe) thin film material is one of the most widely used materials for anisotropic magnetoresistance effect sensors because of its low cost,considerable AMR effect,low coercivity,high sensitivity and low saturation magnetic field.The numerical simulation of the magnetization process and anisotropic magnetoresistance of anisotropic magnetoresistive films is of great significance for improving the performance of anisotropic magnetoresistive sensors.In this paper,the magnetization reversal process of iron nickel nano-elements is studied by finite element method and multi-physics coupling.The relationship between the angle between the electric field and the magnetization direction and the resistivity was verified by the numerical method of coupled micromagnetism and Maxwell's equation.The effects of aspect ratio,film thickness and periodicity on the magnetization reversal of the rectangular magnetoresistive film material and the formation conditions of the vortex state were studied by Nmag micromagnetic software.This paper also studies the magnetization process and resistance variation of single-axis single-domain SW model and multi-domain model in different external fields.Combined with Nmag micromagnetic simulation and FEniCS electrostatic partial differential equation,the results show that the calculated AMR is slightly deviated from the linear relationship with cos~2?.The nonlinear part is caused by the uneven distribution of the demagnetizing field and the area with large demagnetizing field.The formation of a magnetization reversal nucleus results in non-uniformity in the distribution of magnetic moments.In the model with multi-domain structure,the AMR changes greatly when the Bloch wall is formed,and the AMR hardly changes during the domain wall displacement,but the magnetization changes.Studies have shown that the formation of uniform magnetized samples is critical to improving the linear performance of magnetic sensors.In addition,this study further shows that the use of numerical simulation instead of a simple magnetic moment consistent rotation model is of great significance for optimizing the performance of AMR sensors.In this paper,after studying the rectangular AMR magnetoresistive film,the Aber sensor barber electrode was also studied.In we selected three models with a ratio of 1/2,1/4,and 1/14,respectively,and as the aspect ratio increases,the AMR value also increases.The results show that it is important to choose the appropriate aspect ratio to improve the AMR value of the AMR sensor and improve the linearity of the sensor.Then,the paper compares the barber electrode model of the reluctance strip and the traditional barber electrode model.The comparison of the current distribution state and the AMR performance of the two models shows that the barber electrode model with the magnetoresistive layer cut off has better current biasing effect and the resistance change near the zero magnetic field compared with the traditional barber electrode model.The rate is also significantly higher than the traditional barber electrode model.The barber electrode model with the magnetoresistive layer cutoff can effectively improve the sensitivity of the sensor near the zero magnetic field.Finally,the paper also compares the barber electrode model with no sharp corner design and the barber electrode model with 60°sharp angle at both ends.By analyzing the magnetic moment distribution and resistance change law under different states,the 60°sharp angle design can significantly reduce the influence of the demagnetizing field on the magnetic moment distribution of the model edge,and increase the uniformity of the magnetic moment distribution,thus improving the model linear performance of resistance variation. |
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