title: Anomalous phase diagram of ferroelectric (Ba,Ca)TiO3 single crystals with giant electromechanical response.
abstract: We report the anomalous phase evolution in ferroelectric single crystals Ba1-xCaxTiO3 (0.02<x<0.34), and demonstrate the significant effects of quantum fluctuation on the ferroelectric phase transition. In addition, large electromechanical responses in this class of crystals are also demonstrated. Our results indicate that an effective approach to control the ferroelectricity of perovskite oxide can be realized not only by the covalency between A site atom and oxygen but also by the substitution of A site with small ions with off-centering nature. Theoretical calculations support the idea that the off-center displacements of the smaller Ca ions in the Ba-site play an important role in the exotic natures of Ba1-xCaxTiO3.
authors.affiliation: ERATO, Japan Science and Technology Agency, 3-5 Sanbanchou, Tokyo 102-0075, Japan.
authors.forename: Desheng
authors.initials: D
authors.lastname: Fu
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Itoh
authors.forename: Shin-ya
authors.initials: SY
authors.lastname: Koshihara
authors.forename: Taichi
authors.initials: T
authors.lastname: Kosugi
authors.forename: Shinji
authors.initials: S
authors.lastname: Tsuneyuki