Barium Titanate-Coated Cobalt Ferrite Core–Shell Magnetoelectric Nanoparticles for Wireless Actuation Technologies

We report a deposition pathway for barium titanate (BTO) onto hydrophobically coated cobalt ferrite (CFO) nanoparticles, resulting in the formation of magnetoelectric core-shell nanoparticles. Our strategy utilizes a bimetallic Ba and Ti oleate (BTOle) precursor, which hydrophobically interacts with dimethyl-dioctadecyl-ammonium bromide (DDAB)-stabilized CFO particles during an interfacial phase transfer step. Thermal post-treatment yields a crystalline structure comprising distinguishable BTO and CFO phases, with BTO adopting a distorted cubic to tetragonal crystal phase. Magnetoelectric characterization yields a millivolt voltage-range output associated with the mechanical coupling between the piezoelectric and magnetostrictive phases. This method circumvents traditional sol-gel limitations and phase transfer hurdles, offering a streamlined route for fabricating magnetoelectric nanoparticles. Our results suggest magnetoelectric particles are suitable for incorporation in wireless actuation technologies.