Magnetoelectric BaTiO ₃ /CoFe ₂ O ₄ Thin‐Film Meshes for Neuronal Differentiation

ABSTRACT

Magnetoelectric composites offer a powerful route for remotely converting magnetic stimuli into local electrical cues, with promising biomedical applications in electrical stimulation. In strain‐mediated magnetoelectric heterostructures, however, efficient coupling depends strongly on crystallinity, interface quality, and mechanical boundary conditions. Epitaxial thin films provide excellent crystallinity and well‐defined interfaces, but substrate clamping suppresses strain transfer and limits magnetoelectric performance. Here, we report a freestanding magnetoelectric mesh based on an epitaxial BaTiO ₃ /CoFe ₂ O ₄ bilayer and demonstrate its use for magnetic‐field‐driven neural progenitor cell differentiation. By systematically relaxing the mechanical boundary condition from substrate‐clamped films to polydimethylsiloxane (PDMS)‐transferred structures and ultimately to freestanding meshes, we show a progressive enhancement in the magnetoelectric coupling coefficient. This enhancement is directly reflected in improved neural progenitor differentiation, establishing magnetoelectric transduction as a key driver of the observed cellular response. Our results show that engineering mechanical compliance in epitaxial magnetoelectric platforms can substantially improve biofunctional stimulation, providing a design strategy for next‐generation cell culture, differentiation, and wireless stimulation systems.