Highly Sensitive DC Magnetic Field Sensor Based on Nonlinear ME Effect

Under a high ac excitation field, the output voltage of magnetoelectric (ME) composite at the third harmonic is linearly proportional to dc magnetic field, which makes it an excellent dc magnetometer. We fabricated a PZT and metallic glass (MG) composite with a multi-push-pull mode configuration, which has large values of linear ME coefficient. We systematically investigated the nonlinear ME effect of the PZT/MG composite at its electric-mechanical resonance frequency of 30 kHz. The sensitivity to dc magnetic field is studied under different ac excitation field and dc bias field. We found that the highest sensitivity is 17.6 V/Oe at zero bias field. The nonlinear ME magnetic sensor has been demonstrated with a limit of detection of 2 × 10-5Oe to dc magnetic field.