用于实验室环境磁场检测的高灵敏度GMI磁传感器研制

Development of high-sensitivity GMI magnetic sensor for laboratory environmental magnetic field detection

小型化、高灵敏、可实时精确测量实验室环境磁场的专用磁传感器,对确保实验室内精密设备仪器的正常运行具有重要意义。该文研制了一种基于巨磁阻抗(GMI)效应的磁传感器,传感器以钴基非晶丝为核心敏感材料,采用非对角激励方式测量磁场变化。在电路设计上,由预编程晶振与单稳态多谐振荡器构成磁传感器的激励信号发生电路,由反相缓冲器、开关检波和反相积分器构成磁传感器的信号处理电路。性能测试结果表明在–60 000~60 000 nT的磁场强度范围内,传感器分辨率可达750 pT,24 h漂移量≤3 nT,非线性度<0.5%,达到了实验室实际环境磁场测量要求。

The special magnetic sensor with miniaturization, high sensitivity and real-time precision measurement of laboratory environment magnetic field is of great significance to ensure the normal operation of precision equipment and instruments in the laboratory. A kind of magnetic sensor based on giant magnetic-impedance(GMI)effect is developed in this paper. The sensor takes cobalt-based amorphous wire as the core sensitive material, and measures the magnetic field change by off-diagonal excitation. In circuit design, the excitation signal generating circuit of magnetic sensor is composed of pre-programmed crystal oscillator and monostable multivibrator, and the signal processing circuit of magnetic sensor is composed of reverse buffer, switch detector and inverse integrator.The performance test results show that in the magnetic field intensity range of –60 000~60 000 n T, the sensor resolution can reach 750 pT, the 24 h drift≤3 nT, and the nonlinearity <0.5%, which meets the requirements of the actual environmental magnetic field measurement in the laboratory.