A Labile Hydride Strategy for the Synthesis of Heavily Nitridized BaTiO3

Published

December 1, 2015

Author(s)

Takeshi Yajima, Fumitaka Takeiri, Kohei Aidzu, Hirofumi Akamatsu, Koji Fujita, Wataru Yoshimune, Masatoshi Ohkura, Shiming Lei, Venkatraman Gopalan, Katsuhisa Tanaka, Craig Brown, Mark Green, Takafumi Yamamoto, Yoji Kobayashi, Hiroshi Kageyama

Abstract

Oxynitrides, which have been explored extensively in the last decade, exhibit various novel properties beyond oxides, including visible light absorption, photocatalytic activity and high dielectric constants. The synthesis of these oxynitrides generally requires high temperature ammonia treatment (800 °C-1300 ° C) of starting regents (e.g. oxides), but the highly reducing conditions as well as the low mobility of N^3- in the lattice put a significant constraint on the compositional/structural versatility and hence resulting properties. Here we describe a novel topochemical synthesis pathway to access an oxynitride using a titanium perovskite oxyhydride as a host. The lability of H- in BaTiO_3-xH_x (x less than or equal to} 0.6) allows N³-/H- exchange to occur at relatively low temperatures (< 500 °C), yielding BaTiO_3-xN_2x/3 (via mixed O-N-H intermediates), which is accompanied by a crossover from metallic to insulating behaviour. BaTiO_3-xN_2x/3 (x ≅ 0.6, 0.4) is tetragonal and exhibits ferroelectricity, with a critical temperature, TC, comparable to BaTiO₃. The present results suggest that this "labile hydride" strategy has the potential to open a new avenue for the preparation of various oxynitrides and perhaps other mixed anionic compounds.

Citation

Nature Chemistry

Volume

7

Pub Type

Journals

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Keywords

neutron scattering, structure

Citation

Yajima, T. , Takeiri, F. , Aidzu, K. , Akamatsu, H. , Fujita, K. , Yoshimune, W. , Ohkura, M. , Lei, S. , Gopalan, V. , Tanaka, K. , Brown, C. , Green, M. , Yamamoto, T. , Kobayashi, Y. and Kageyama, H. (2015), A Labile Hydride Strategy for the Synthesis of Heavily Nitridized BaTiO₃, Nature Chemistry, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=917734 (Accessed April 19, 2024)