Eleventh Order Lamb Wave Mode Biconvex Piezoelectric Lorentz Force Magnetometer for Scaling Up Responsivity and Bandwidth

Abstract

We report the novel use of a higher harmonic Lamb wave modes to realize a piezoelectric readout Lorentz force magnetometer (LFM). The proposed design aims to significantly enhance the pre-amplified sensitivity per unit of excitation current (referred to as the responsivity here) relative to the fundamental mode in the same resonator. By exploiting an 11th harmonic Lamb mode biconvex resonator, we experimentally demonstrate over 5 times increase in responsivity over another device based on the fundamental mode. Compared to state-of-art capacitive LFMs encapsulated in vacuum for high quality factor (Q), the 11th order Lamb wave LFM reported herein boasts a ten-fold boost to responsivity (26.8ppm/mT) in ambient (i.e. atmospheric) pressure.