Twin-detector sensor of Co-rich amorphous microwires to overcome GMI fluctuation induced by ambient temperature

Giant magnetoimpedance (GMI) fluctuation induced by ambient temperature was particularly discussed based on experiments accomplished with melt-extracted Co-rich amorphous microwires. The specimen with Cu electro-plated two-end was placed in a calorstat in magnetically shielded space (MSS), and the impedance stability was measured by means of a precision impedance analyzer in a temperature range of 0°C to 320°C. Experimental results indicated that the critical transition temperature of GMI fluctuation is obtained at 80°C, and even the impedance stability sharply deteriorates with the temperature increasing to 320°C for the increase of resistivity, the intensity of magnetic polarization, and quasi-magnetocrystalline anisotropy energy. Comparison with conventional single-detector sensor (SDS), a novel design mode of twin-detector sensor (TDS) by the differential method at the working temperature of 0°C-80°C, was presented for effectively overcoming GMI fluctuation to achieve the relatively high-precision measurement of weak magnetic field. It therefore is expected that TDS is favorable for optimizing the systematic structure design of a high-resolution magnetic sensor.