Synthesis and Characterization of Fe₃O₄-Functionalized BaTiO₃ Nanowires for Magnetically Driven Alignment

Abstract

Maximizing macroscopic polarization through structural engineering is a fundamental prerequisite for enhancing the electromechanical conversion efficiency of piezoelectric materials. However, conventional approaches relying on zero-dimensional (0D) nanoparticles (NPs) or randomly oriented fillers inherently suffer from discontinuous polarization pathways due to the absence of structural alignment. This lack of connectivity disrupts the formation of electrical percolation networks, severely limiting the effective utilization of intrinsic ferroelectric responses. To address these limitations, this study utilizes high-aspect-ratio piezoelectric BaTiO₃ nanowires (BTO NWs) to establish directionally continuous polarization pathways. Superparamagnetic Fe₃O₄ NPs were uniformly functionalized onto the NWs surface via a PVP-assisted co-precipitation method, producing magnetically responsive Fe₃O₄-functionalized BTO NWs (FBTO NWs) while preserving the piezoelectric core. These FBTO NWs were then aligned within a polymer matrix using an external magnetic field to induce structural anisotropy. Polarization–electric field (P–E) hysteresis measurements confirmed that the remnant and saturation polarization were significantly maximized when the FBTO NWs were aligned parallel to the electric field. This study demonstrates a robust strategy for overcoming the limitations of isotropic structures, resulting in significantly improved polarization via programmable magnetic alignment.