GMI磁传感器内部灵敏度与噪声特性研究

Study on Properties of the Intrinsic Sensitivity and Noise of GMI Magnetic Sensor

建立了非晶带GMI敏感元件的灵敏度和噪声理论模型,计算了其灵敏度和磁噪声在不同易轴方向和外磁场应用条件下的响应特性.通过改变易轴方向、外磁场及直流偏置场对非晶带敏感元件进行了优化,其内部磁噪声达到了fT/Hz水平.分析了内部灵敏度、工作点和磁噪声水平对GMI磁传感器性能的影响,结果表明,在GMI磁传感器设计时,应综合考虑灵敏度和噪声的指标,采取折衷的方案对敏感元件进行优化是合理的,这为实现高灵敏度、低噪声、稳定性好的GMI磁传感器提供了理论依据.

The theory model of the sensitivity and magnetic noise of a GMI sensing element consisting of an anisotropic amorphous ribbon was established. For different anisotropy directions and applied external fields, a calculation of the intrinsic sensitivity and magnetic noise of the GMI magnetic sensor was presented. Through varying anisotropy direction, external field and the DC bias field, the amorphousribbon sensing element was numerically optimized and the intrinsic noise reached fT√Hz. The effect of the intrinsic sensitivity, working point and magnetic noise level on the performance of the GMI magnetic sensor was analyzed. The result suggests that it is reasonable by making a compromise of the sensitivity and magnetic noise to optimize the sensing element. This provides references in theory for high sensitivity, low noise and good stability GMI magnetic sensor.