Highly Sensitive Magneto-Mechano-Electric Magnetic Field Sensor Based on Torque Effect

Abstract

Magnetic field sensors based on the strain-mediated magnetoelectric (ME) coupling are usually bulky and energy-consuming due to the requirement for DC magnetic bias field, and the use of piezoelectric ceramics or single crystals cannot bear overlarge strain due to their fragility. Here, we demonstrate a stress-mediated ME sensor operating in torque mode without magnetic bias field. Combined with elastic layers, the NdFeB permanent magnets induce compressive stress on the piezoelectric layer via torque effect under a weak magnetic field. The contribution from d <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">33</sub> piezoelectric coefficient is dominant to the ME effect, and a large ME voltage of 2480 mV is observed at 13.6 Oe. At the resonate frequency of 138.7 Hz, magnetoelectric coefficient is found to be as high as 6.08 V/cm Oe. Our results reveal that the proposed ME sensor mediated by stress is excellent in performance and reliable in durability, which is promising for magnetic sensor applications.