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 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 magnetoelectric coupling effect. Magnetoelectric sensors based on longitudinal bending, circular bending, and longitudinal extension resonators exhibit excellent performance, with resonance magnetoelectric coefficients of 2.17 V/(cm·Oe), 13.29 V/(cm·Oe), and 15.2 V/(cm·Oe), respectively. Meanwhile, the proposed magnetoelectric sensors can detect weak magnetic fields at the pT level. The limit of detection (LOD) under resonance frequency for magnetoelectric sensors based on longitudinal bending resonator, circular bending resonator, and longitudinal extension resonator can reach up to 39.49 pT, 7.99 pT, and 6.28 pT, respectively, which are competitive among other typical magnetoelectric 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 °C to 70 °C. With enhanced performance, magnetoelectric sensors based on hollowed-out resonant structures demonstrate great potential for applications such as current detection, position sensing, and industrial control.