Magnetic field sensing with a single piezoelectric ceramic disk: Experiments and modeling

Abstract

This study reports on the magnetoelectric coupling in a single piezoelectric ceramic disk subjected to both ac and dc magnetic fields perpendicularly applied to the sample’s plane. Eddy currents are induced within the electrodes of the ceramic by ac magnetic flux via the Lenz–Faraday equation and yields Lorentz forces and stresses which are transferred to the piezoelectric ceramic. This latter transduces stress into electrical charges through electromechanical coupling in radial mode. The measured output magnetoelectric current could be successfully modeled using piezoelectric equations providing the inductively coupled voltage between the electrodes of the ceramic is taken into account. This voltage originates from the ac magnetic flux through the experimental loop, which is not a perfect short-circuit and yields two other contributions to the total current: piezoelectric current due to the induced electric field and the dielectric loop current. Radial velocity measurements confirmed the distinct contributions to the current. Thus, room temperature magnetic field detection is achievable using this single piezoelectric disk with a good sensitivity and linear response versus dc magnetic field change.