A Magnetic Sensor Based on the Nonlinear Effect of Co-Rich Amorphous Wire

A DC voltage induced by a DC magnetic field was observed for a coil with a Co-rich amorphous wire (FeCoSiB) as the core when an AC current flowed through the coil. The coil was 40 turns wound around a FeCoSiB amorphous wire with a diameter of 0.1 mm and a length of 8 mm. The magnitude of the DC voltage was determined by the frequency of the AC current, the amplitude of the AC current, and the applied DC magnetic field. When the sine wave current was 78 mA and the frequency was 6.8 MHz, a peak value of about 90 mV/Gauss DC voltage was observed. This phenomenon might have a relationship with the nonlinearity of the coil with the FeCoSiB amorphous wire as the core. A magnetic sensor with only an amplifier and a low-pass filter was developed using this effect.