Theoretical Investigation of a Resonant Magnetoelectric Sensor Based on a Piezoelectric-on-Silicon Length-Extensional Mode Resonator

Recently, piezoelectrically driven resonant magnetoelectric sensors have attracted increasing interest owing to their high sensitivity, compact size, and low power consumption. Here, we theoretically demonstrate the magnetic sensing performances of using the magnetic field-dependent magnetomechanical effects in a thin-film piezoelectric-on-silicon (TPoS) resonator. Equivalent circuit models are established to describe the sensing and intrinsic thermal noise characteristics of the mechanical resonator. In addition, the thermal-magnetic noise due to magnetic losses of magnetostrictive films is also considered into the modeling. Based on the signal and noise model, the influence of mechanical quality factor is analyzed in different driving cases. It is concluded that the limit of detection (LOD) can be significantly improved by increasing the quality factor in the case of low voltage driving, while the enhancement of quality factor has little effect on improving the LOD in the case of higher voltage driving, implying the importance of magnetic noise suppression.