Electrophoretic deposition of multiferroic BaTiO3/CoFe2O4 bilayer films

Electrophoretic deposition (EPD) method was used to fabricate multiferroic BaTiO3/CoFe2O4 (BTO/CFO) bilayer film with a thickness up to 15 μm. Sediment volumes and zeta potential studies showed suspensions of BTO in ethanol–acetylacetone (1:1 in volume) and CFO in acetylacetone with 0.20 wt% PEI added were the most stable dispersion systems, respectively. Thoroughly dispersed suspensions of BTO and CFO were formed under ultrasonic agitation for 30 and 50 min. Effects of particle size distribution on deposition process were also investigated. XRD, SEM analysis showed the annealed bilayer film had two well-defined BTO/CFO phases and dense microstructure. The obtained bilayer films exhibited evident ferroelectricity (Ps = 14.1 μC cm−2) and ferromagnetism (Ms = 148.7 emu cm−3 (in plane)) simultaneously at room temperature.