Prediction and optimization for linearity of MTJ magnetic sensors based on single-domain model

In the processing fabrication of MTJ stacks, the Neel and magnetostatic coupling induce a strong interlayer coupling field along the hard-axis direction, and the utilization of the magnetic bias field along the easy-axis direction makes the response of MTJ nonlinear. In this paper, we researched the influence of the interlayer coupling field and permanent bias field on the linearity of MTJ magnetic sensor. When |h_y0| <; 1, and the linear range (1-|h_y0|) meets the demand, the magnetization of the reference layer should be opposite to the direction of interlayer coupling field for a higher sensitivity and practical dR ratio. The prediction and optimization of the linearity were also researched by apply an appropriate bias field.