Creating High Aspect Ratio Magnetostrictive Flakes to Enhance Magnetoelectric Polymer Composites

Polymer-based magnetoelectric materials form a technologically significant class of magneto-polymer composites which show promise for the production of low-cost and mechanically durable sensors, energy harvesters, and transducers. The use of a particle magnetostrictive phase in these composites offers a scalable path to producing large-area magnetoelectric materials and, so, is highly attractive. A key challenge for these composites is improving the coupling between the particle and polymer phases. In this work, we explore the use of shape anisotropy in galfenol flake particles as a means of bestowing magnetoelectric anisotropy. Cryogenic ball milling is used as a means to produce particulates, which are distributed and aligned in P(VDF-TrFE) composite films. A direction-specific, bias-free magnetoelectric coupling as high as 46.27 mV/cm·Oe was achieved. The use of this material in an energy harvesting device yielded peak energy harvesting power densities of 46.97 and 2.03 μW/cm³ for vibrational and magnetic fields, respectively.