Bilayer thick structures based on CoFe2O4/TiO2 composite and niobium-doped PZT obtained by electrophoretic deposition

In view of developing new structures and processes for the production of magnetoelectric materials, bilayer thick structures made of cobalt ferrite (CoFe2O4)/titanium dioxide (TiO2) composite and niobium-doped lead zirconate titanate (PZTN) were grown on silver-coated alumina substrates by electrophoretic deposition (EPD) from ethanol-based colloidal suspensions. A first co-deposition from a CoFe2O4/TiO2 suspension was followed, after heat treatments of the electrodeposited composite layer, by a second deposition from a PZTN suspension. Each deposition was performed at constant voltage while recording the current. High density structures keeping the same stoichiometry of the deposited particles were observed after sintering. Composition, thickness and relative density of the layers were investigated by Energy Dispersive X-ray Spectroscopy (EDXS) and Scanning Electron Microscopy (SEM) analyses, while the crystalline phases were identified by X-ray diffraction (XRD). Ferroelectric, hysteresis loops and piezoelectric response of the bilayer thick structures were measured resulting in good piezoelectric activity of the poled structures.