Dual-drive DC magnetic sensor based on converse magnetoelectric coupling effect

Abstract

This study presents an innovative design for a direct current (DC) magnetic sensor that leverages the converse magnetoelectric (ME) coupling effect along with a novel dual ME coupling structure to significantly enhance sensitivity in DC magnetic field detection. A sensitivity model was developed, and the impact of array quantity on both sensitivity and the signal-to-noise ratio (SNR) was analyzed. Comprehensive theoretical analysis and experimental validation were conducted to evaluate the SNR performance of the array structure. The design incorporates periodic magnetic flux changes induced in two Metglas-PZT8-Metglas ME coupling structures by the investigated magnetic field. These changes are detected by a pickup coil, which generates the measurement output. The dual-drive configuration substantially increases signal strength and facilitates precise magnetic field measurements without altering the external magnetic field distribution. By modulating the drive voltage, the sensor's sensitivity is linearly adjustable, thereby mitigating nonlinearity. Furthermore, by examining the phase-frequency characteristics of the output signal, the sensor's capability to determine the direction of the magnetic field was confirmed. This sensor offers low cost, high sensitivity (10.51 mV/μT), low detection limits (1 nT), and a broad dynamic range (1 nT to 300 μT), making it suitable for precise measurements of geomagnetic field strength and direction. This development represents a cost-effective approach to producing compact, efficient DC magnetometers.