Structural optimization of magnetic vortex domain and the modulation of magnetic sensor performance

Hysteresis presents a significant challenge in magnetic sensors. While Tunnel Magnetoresistance (TMR) sensors employ various techniques to mitigate hysteresis, measurement errors caused by it cannot be fully eliminated, despite advancements in sensor fabrication and back-end process optimization. This paper introduces a method that incorporates vortex structures in the TMR free-layer and utilizes micromagnetic simulations to examine the influence of diameter (d) and thickness (t) of the free-layer on sensitivity and measuring range of the sensor. The study reveals that sensitivity is directly proportional to the diameter and inversely proportional to the thickness, while the measuring range is proportional to the thickness and inversely proportional to the diameter. Empirical formulas between these parameters is established, and the limiting values for diameter and thickness are identified, offering valuable insights for the design of vortex-based TMR sensors.