Retainable large magnetoelectric coupling in BiFeO3@CoFe2O4 core-shell nanoparticle embedded P(VDF-TrFE) matrix

Abstract

Flexible magnetoelectric composite devices have exceptional features and potential in peculiar scenes. However, maintaining the magnetoelectric response under extreme bending conditions remains a challenge. Polyvinylidene fluoride-based polymers, possessing favorable piezoelectric properties and high flexibility, provide a viable solution for magnetoelectric composites. This work constructed multiferroic core-shell nanoparticle-embedded flexible membranes and achieved a retainable high magnetoelectric (ME) coupling coefficient in the curved composite materials. A maximum ME coefficient of 74 mV cm−1 Oe−1 was obtained, far higher than the 0–3 ME nanocomposites reported thus far. The ME coefficient can be maintained above 40 mV cm−1 Oe−1 when the bending angle is less than 90° and expresses high sensitivity within the Hdc range of 100–2400 Oe. Based on crystal structure analysis and phase-field simulation, the synergy magnetoelectric effects accounting for the multiferroic core-shell nanoparticles, copolymer matrix, and magnetic cores contribute to the promoted ME coefficient in the flexible composites. This work provides a feasible pathway for next-generation flexible devices in the wearable and portable fields.