Modeling of magnetic sensor based on BAW magnetoelectric coupling micro-heterostructure

Sensors actuated by bulk acoustic wave (BAW) have attracted lots of attention due to their high sensitivity, GHz-level high frequency, and small size. Different from the previous studies, the performance optimization of magnetoelectric (ME) micro-heterostructure has been adequately considered in this work. We constructed a micro-level model of the magnetic sensor based on BAW ME coupling 2~5 layers micro-heterostructure. Its properties working under both direct current bias and high-frequency alternating magnetic field were systemically analyzed. The results show that the sensitivity and linearity of the sensor can be optimized by adjusting the layer number of the device and the bias magnetic field applied to the ME heterostructure. Eventually, the highest sensitivity of 3.24 V/Oe . cm has been achieved on the magnetic sensor with three-layer structure at the first resonant frequency of 2.2 GHz, and linearity can be strictly controlled within 2% with measuring range of 75~150 Oe. These results has demonstrated that the micro-model of the BAW ME coupling micro-heterostructure, and realized a method to improve its sensitivity and linearity by optimizing the device structure and test conditions. This achievement will further guide the structural design and performance optimization of ME coupling devices.