Concurrent operational modes and enhanced current sensitivity in heterostructure of magnetoelectric ring and piezoelectric transformer

A heterostructure possessing two concurrent operational modes: current sensing (CS) mode and current transduction (CT) mode and an enhanced current sensitivity associated with the CT mode is proposed by combining a magnetoelectric ring (MER) with a piezoelectric transformer (PET). The MER is a ring-shaped magnetoelectric laminate having an axially polarized Pb(Zr, Ti)O₃ (PZT) piezoelectric ceramic ring sandwiched between two circumferentially magnetized, inter-magnetically biased Tb_0.3Dy_0.7Fe_1.92 (Terfenol-D) short-fiber/NdFeB magnet/epoxy three-phase magnetostrictive composite rings, while the PET is a Rosen-type PZT piezoelectric ceramic transformer. The current sensitivity (S_I) and magnetoelectric voltage coefficient (α_V) of the heterostructure in the two operational modes are evaluated theoretically and experimentally. The CS mode provides a large S_I of ∼10 mV/A over a flat frequency range of 10 Hz−40 kHz with a high resonance S_I of 157 mV/A at 62 kHz. The CT mode gives a 6.4-times enhancement in resonance S_I, reaching 1000 mV/A at 62 kHz, as a result of the amplified vortex magnetoelectric effect caused by the vortex magnetoelectric effect in the MER, the matching of the resonance frequencies between the MER and the PET, and the resonance voltage step-up effect in the PET.