The giant magneto-impedance (GMI) effect has been, since its discovery, one of the most promising technologies in the development of magnetic sensors. Features such as high sensitivity, stability and low cost are the main reasons for the development of this type of magnetometers. This study reports the design, implementation and experimental characterisation of a high sensitivity GMI gradiometer, aimed at measuring low-intensity magnetic fields. A first-order gradiometer was designed, based on the impedance phase characteristics of two Co ₇₀ Fe ₅ Si ₁₅ B ₁₀ amorphous ribbon-shaped sensors connected to an electronic circuit that converts the magnetic field into an output voltage. The developed prototype can operate not only as gradiometer but also as two separate magnetometers, which allows it to incorporate a compensation system against deviations in the biasing field of the GMI sensors. The experimental results for the gradiometer showed a sensitivity of 99 mV/μT, a measuring range of ±30 μT, a magnetic noise of 5 nT Hz ^-1/2 at 5 Hz and a resolution of 40 nT within a 500 Hz bandwidth. The compensation system has shown a settling time of 1.6 s for perturbations in the range ±10 μT with a steady-state error <;0.02%. All experiments were performed in an unshielded environment.

中文翻译：

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具有干扰补偿系统的高灵敏度GMI梯度仪的设计，实现和实验特性

自发现以来，巨大的磁阻抗（GMI）效应一直是磁传感器开发中最有前途的技术之一。高灵敏度，稳定性和低成本等特性是开发这种磁力计的主要原因。这项研究报告了旨在测量低强度磁场的高灵敏度GMI梯度仪的设计，实现和实验特性。基于两个Co ₇₀ Fe ₅ Si ₁₅ B ₁₀的阻抗相位特性，设计了一阶梯度仪 非晶带状传感器，连接到电子电路，将磁场转换成输出电压。所开发的原型不仅可以用作梯度仪，还可以作为两个单独的磁力仪，这使其可以结合补偿系统来抵抗GMI传感器的偏置场中的偏差。梯度计的实验结果表明，灵敏度为99 mV /μT，测量范围为±30μT，在5 Hz时的磁噪声为5 nT Hz ^-1/2，在500 Hz带宽内的分辨率为40 nT。补偿系统显示，在±10μT范围内的扰动建立时间为1.6 s，稳态误差<; 0.02％。所有实验均在非屏蔽环境下进行。