Solidly Mounted Bulk Acoustic Wave Resonant Magnetic Field Sensor Based on Magnetoelastic Effect

This paper reports a nano-electromechanical resonant magnetic field sensor by integrating solidly mounted bulk acoustic wave resonator (SMR-BAW) with an ultra-sensitive magnetoelastic amorphous film. By exploiting Mason equivalent model and transmission line calculation method, we theoretically demonstrate the capability to realize both excellent resonance characteristic and ultra-high magnetic field sensitivity in such composite configuration. The proposed device achieves an outstanding maximum magnetic sensitivity of 172 MHz/Oe around resonance frequency of 2.836 GHz with quality factor of 552. Furthermore, we have also investigated the dependence of maximum sensitivity on the thickness of magnetic sensitive layer, which indicates there exists an optimal thickness value to maximize the sensitivity of the sensor. The demonstrated device holds great promise for ultra-low magnetic field detection in civilian and military applications.