Magnetoelectric Sensors With Hollowed-Out Resonant Structure Fabricated by Laser Cutting

In this work, the laser cutting method is applied to the fabrication of magnetoelectric (ME) sensors, particularly for machining hollowed-out resonant structures. Three types of hollowed-out resonant structures, i.e., longitudinal bending, circular bending, and longitudinal extension resonators, are fabricated using laser cutting. Experimental results reveal that the hollowed-out resonant structure significantly enhances the ME coupling effect. ME sensors based on longitudinal bending, circular bending, and longitudinal extension resonators exhibit excellent performance, with resonance ME coefficients of 2.17, 13.29, and 15.2 V/(cm $\cdot $ Oe), respectively. Meanwhile, the proposed ME sensors can detect weak magnetic fields at the pT level. The limit of detection (LOD) under resonance frequency for ME sensors based on longitudinal bending resonator, circular bending resonator, and longitudinal extension resonator can reach up to 39.49, 7.99, and 6.28 pT, respectively, which are competitive among other typical ME sensors. The temperature tolerance test indicates that the circular bending resonator presents the highest temperature stability, with the resonance frequency drift less than 3% in the temperature range from $20~^{\circ }$ C to $70~^{\circ }$ C. With enhanced performance, ME sensors based on hollowed-out resonant structures demonstrate great potential for applications, such as current detection, position sensing, and industrial control.