Snap-through instability-driven enhancement of magnetoelectric coupling in soft electrets

Abstract

Conventional magnetoelectric (ME) systems often suffer from the reduced conversion efficiency at low frequencies due to the low power input and relatively small ME coupling coefficient, constraining their applications in magnetic sensing and energy harvesting. In this work, we present a novel approach of utilizing the snap-through instability of soft ME materials to enhance their electric responses in low-frequency magnetic environments. This snapping soft ME material, also called the snapping ME electret (SMEE), is designed as an elastomeric arch with tunable residual magnetic flux density and embedded net charges. The high performance of SMEEs stems from fact that, when staying at a critical instability state, any small magnetic perturbation would induce the snap-through behavior of it and generate high-frequency electrical pulses. Here, a theoretical model based on the instability mechanics of SMEEs is presented and used to predict the strong ME coupling effect near its critical state. Experiments are also conducted to confirm the enhanced ME coupling of SMEEs across a broad range at extremely low frequencies. The SMEE proposed here demonstrates an interesting and effective mechanical pathway to amplify and tune the coupling between magnetic and electric fields.