Electrical and magnetic properties of bilayered BaTiO3–Ni thick films prepared via a combined method of electrophoretic deposition and screen printing

Abstract

Thick film BaTiO3 (BTO)–Ni composites were prepared on alumina substrates via a combined method of electrophoretic deposition (EPD) and screen printing technique. During the EPD process, a Ni/alumina substrate was used as a deposited electrode (cathode), which was prepared via the screen printing method. Microstructures, electrical property and magnetic property of the layered composites were studied. Results reveal that the porous composites present non-ferroelectric property and negative resistance effect, in which the former could be attributed to the fact that the sintering was conducted in a reducing atmosphere. Furthermore, the out-of-plane and in-plane leakage current characteristics could testify the homogeneity of the thick films in different directions via the electric fields which correspond to the leakage current peaks. The non-uniformity of the composite in the vertical direction may be related to the instability of BTO particles in suspension. Also, the dielectric constant in the out-of-plane mode decreases with increasing frequency owing to the existence of space charges. In addition, the bilayered films exhibit magnetic anisotropy, which could be ascribed to the interfacial stress between alumina substrates and Ni layers.