title: Epitaxial thin films of ATiO(3-x)H(x) (A = Ba, Sr, Ca) with metallic conductivity.
abstract: Epitaxial thin films of titanium perovskite oxyhydride ATiO(3-x)H(x) (A = Ba, Sr, Ca) were prepared by CaH(2) reduction of epitaxial ATiO(3) thin films deposited on a (LaAlO(3))(0.3)(SrAl(0.5)Ta(0.5)O(3))(0.7) substrate. Secondary ion mass spectroscopy detected a substantial amount and uniform distribution of hydride within the film. SrTiO(3)/LSAT thin film hydridized at 530 °C for 1 day had hydride concentration of 4.0 × 10(21) atoms/cm(3) (i.e., SrTiO(2.75)H(0.25)). The electric resistivity of all the ATiO(3-x)H(x) films exhibited metallic (positive) temperature dependence, as opposed to negative as in BaTiO(3-x)H(x) powder, revealing that ATiO(3-x)H(x) are intrinsically metallic, with high conductivity of 10(2)-10(4) S/cm. Treatment with D(2) gas results in hydride/deuteride exchange of the films; these films should be valuable in further studies on hydride diffusion kinetics. Combined with the materials' inherent high electronic conductivity, new mixed electron/hydride ion conductors may also be possible.
authors.affiliation: Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yajima
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kitada
authors.forename: Yoji
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Tatsunori
authors.initials: T
authors.lastname: Sakaguchi
authors.forename: Guillaume
authors.initials: G
authors.lastname: Bouilly
authors.forename: Shigeru
authors.initials: S
authors.lastname: Kasahara
authors.forename: Takahito
authors.initials: T
authors.lastname: Terashima
authors.forename: Mikio
authors.initials: M
authors.lastname: Takano
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kageyama