Microstructure and multiferroic properties of BaTiO3/CoFe2O4 films on Al2O3/Pt substrates fabricated by electrophoretic deposition

BaTiO3/CoFe2O4 bilayer films on high temperature resistant Al2O3/Pt substrates were fabricated using the electrophoretic deposition (EPD) method. Powder synthesis, suspension preparation and kinetics of deposition were investigated in detail. Two different sintering temperatures were tested and the resultant microstructure and properties of ceramic films were investigated. The composite films sintered at a temperature of 1200 °C/2 h yielded optimal microstructures and properties. The obtained bilayer films had a dense structure with no phase diffusion or passive layer. Besides to ferroelectric and magnetic properties, magnetoelectric (ME) coupling properties were also confirmed by the magnetic anisotropy and magnetic field induced polarization investigation. The composite films showed a increased Ps from 16.2 to 16.85 μC/cm2 with variations ΔPs of 4% when the magnetic field was applied in parallel direction and a decreased Ps from 16.2 to 14.9 μC/cm2 with variations ΔPs of −8% when a normal direction field was applied.