In a search for effective giant magnetoelectric coupling: magnetically induced elastic resonance in Ni-Mn-Ga/P(VDF-TrFE) composites

Abstract

Poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) is a piezoelectric polymer suitable for applications in electromechanical and magnetoelectric (ME) systems. Ni-Mn-Ga alloys exhibit a giant magnetoelastic response related to their structural transformations of martensitic type, accompanied by noticeable volume changes. Together, in a thin film composite containing an ensemble of Ni-Mn-Ga particles (10 wt.%) distributed in the P(VDF-TrFE) piezopolymer, they ensure an unprecedented resonance amplification of the ME effect. Thus, a giant value of ME coefficient of 6.05 V·cm−1· Oe−1 under AC magnetic drive field of 0.2 Oe and DC bias field of 1300 Oe is experimentally observed and discussed. The physical mechanism of the proposed ME response amplification has been explained theoretically through the volume magnetostriction of the magnetostrictive particles and resonant elastic oscillation of the piezoelectric polymer matrix.