Enhanced performance of weak magnetic field sensor based on laminated cantilever: theoretical analysis and experimental verification

The present study introduces a weak magnetic field sensor that utilizes a laminated cantilever structure, consisting of a magnetostrictive layer, a piezoelectric layer, and a substrate layer. Consequently, the transformation from the magnetic signal to the electrical signal is accomplished through the consistent mechanical stress in both layers. A comprehensive theoretical model has been developed to evaluate the impact of key structural parameters on the magnetoelectric sensing performance, enabling the optimization of the device design. By incorporating vanadium (V) as a dopant element, a Zn-V-O film with a piezoelectric coefficient as high as 35 pm/V is fulfilled. Furthermore, the high piezomagnetic properties of Galfenol make it a suitable candidate as a magnetostrictive layer. Sensor prototypes were fabricated for experimental verification through the utilization of MEMS technology. The film was characterized using techniques such as XRD, TEM, and PFM. The magnetoelectric testing experiments indicated that the magnetostrictive coefficient could achieve about 9.32 kV/(cm∙Oe) at resonant frequencies for sensors with varying lengths and a 20 μm thick Si substrate. The proposed sensor exhibits promising potential for improving weak magnetic field detection performance.