Stress state analysis of stress engineered BaTiO₃ thin film by LaNiO₃ bottom electrode

Abstract

Ferroelectric materials with excellent performance without containing lead has been desired for saving human body from a harmful element, lead. The authors have reported BaTiO₃ (BTO) thin films with enhanced ferroelectricity by stress engineering by thermal stress assisted by LaNiO₃ (LNO) bottom electrodes. In the present study, we investigate the local stress state of the BTO and LNO films using TEM techniques. TEM observation reveals that the LNO film is porous structure whereas the BTO film is dense. Electron diffraction and dark field images of the films also reveal that the BTO and LNO films oriented along [001] and [100] directions perpendicular to the film plane, respectively. Another effect on the stressed BTO films, increased Curie temperature owing to the stabilized tetragonal phase, is also reported.