title: A labile hydride strategy for the synthesis of heavily nitridized BaTiO3.
abstract: Oxynitrides have been explored extensively in the past decade because of their interesting properties, such as visible-light absorption, photocatalytic activity and high dielectric permittivity. Their synthesis typically requires high-temperature NH3 treatment (800-1,300 °C) of precursors, such as oxides, but the highly reducing conditions and the low mobility of N(3-) species in the lattice place significant constraints on the composition and structure-and hence the properties-of the resulting oxynitrides. Here we show a topochemical route that enables the preparation of an oxynitride at low temperatures (<500 °C), using a perovskite oxyhydride as a host. The lability of H(-) in BaTiO3-xHx (x ≤ 0.6) allows H(-)/N(3-) exchange to occur, and yields a room-temperature ferroelectric BaTiO3-xN2x/3. This anion exchange is accompanied by a metal-to-insulator crossover via mixed O-H-N intermediates. These findings suggest that this 'labile hydride' strategy can be used to explore various oxynitrides, and perhaps other mixed anionic compounds.
authors.affiliation: Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan.|Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yajima
authors.affiliation: Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan.
authors.forename: Fumitaka
authors.initials: F
authors.lastname: Takeiri
authors.affiliation: Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Aidzu
authors.affiliation: Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Akamatsu
authors.affiliation: Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Fujita
authors.affiliation: Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan.
authors.forename: Wataru
authors.initials: W
authors.lastname: Yoshimune
authors.affiliation: Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan.
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Ohkura
authors.affiliation: Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors.forename: Shiming
authors.initials: S
authors.lastname: Lei
authors.affiliation: Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors.forename: Venkatraman
authors.initials: V
authors.lastname: Gopalan
authors.affiliation: Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.
authors.forename: Katsuhisa
authors.initials: K
authors.lastname: Tanaka
authors.affiliation: NIST Center for Neutron Research, National Institute of Standards and Technology, 100 Bureau Drive, MS 6100, Gaithersburg, Maryland 20899-6100, USA.
authors.forename: Craig M
authors.initials: CM
authors.lastname: Brown
authors.affiliation: School of Physical Sciences, University of Kent, Canterbury, Kent CT2 7NH, UK.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Green
authors.affiliation: Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan.
authors.forename: Takafumi
authors.initials: T
authors.lastname: Yamamoto
authors.affiliation: Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan.
authors.forename: Yoji
authors.initials: Y
authors.lastname: Kobayashi
authors.affiliation: Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan.|CREST, Japan Science and Technology Agency, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Hiroshi
authors.identifier: http://orcid.org/0000-0002-3911-9864
authors.initials: H
authors.lastname: Kageyama