Evaluation of ferroelectricity in BaTiO3 epitaxial thin film using Ca(Mn,Nb)O3 bottom electrode for high-temperature annealing

Abstract

Due to epitaxial strain, epitaxial thin films exhibit unique properties compared with those in bulk. However, the presence of defects within these films disrupts the strain-induced effects. Although high-temperature annealing is a promising way to improve film quality, high temperature weakens bottom electrode materials. To assess epitaxial strain's effects on the mitigation of other factors, there is a need for a novel bottom electrode material that can withstand high temperatures. In this study, we focused on Nb-doped CaMnO3 (CMNO) as a bottom electrode for the evaluation of BaTiO3 ferroelectricity. The CMNO epitaxial film was deposited on (100)SrTiO3 and showed electrical conductivity even after 1100 °C annealing. The ferroelectric material BaTiO3 was also epitaxially grown on CMNO/(100)SrTiO3 substrate, and its ferroelectric properties were evaluated. Finally, we revealed the ability of CMNO/(100)SrTiO3 to withstand temperatures up to 1100 °C as well as the notable enhancement of ferroelectric properties in the BaTiO3 film.