Interfacial Stress Occured with Formation of CoFe₂O₄ Nanopillars in BaTiO₃ Films

Abstract

CoFe₂O₄(CFO)-doped BaTiO₃(BTO) film is one of composite multiferroic materials. In the materials, magnetoelectric effect occurs from the stress of the interface between ferroelectric and ferromagnetic. Therefore, Interfacial stress between BTO and CFO is important for magnetoelectric effect. However, it has not been clearly yet. It is considered that it can reveal the effect on BTO of CFO to comparing different CFO content samples. Then, we fabricated CFO-doped BTO films with various content and measured lattice constant and temperature dependence of dielectric constant for films. As a result, out-of-plane lattice constant of BTO was reduced with the increase of the CFO content. In addition, phase transition temperature of BTO was increased with the increase of the CFO content. Therefore, it is considered that CFO adds some in-plane tensile stress on BTO.