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Title: Topotactic synthesis of strontium cobalt oxyhydride thin film with perovskite structure

The substitution of hydride anions (H{sup −}) into transition metal oxides has recently become possible through topotactic reactions or high-pressure synthesis methods. However, the fabrication of oxyhydrides is still difficult because of their inherently less-stable frameworks. In this study, we successfully fabricated perovskite SrCoO{sub x}H{sub y} thin films via the topotactic hydride doping of brownmillerite SrCoO{sub 2.5} epitaxial thin films with CaH{sub 2}. The perovskite-type cation framework was maintained during the topotactic treatment owing to epitaxial stabilization. Structural and chemical analyses accompanied by X-ray absorption spectroscopy measurements revealed that the doped hydride ions form a two-dimensional network of Co-H{sup −}-Co bonds, in contrast to other reported perovskite oxyhydrides, SrMO{sub 3−x}H{sub x} (M = Cr, Ti, V). The SrCoO{sub x}H{sub y} thin film exhibited insulating behavior and had a direct band gap of 2.1 eV. Thus, topotactic hydride doping of transition-metal-oxide thin films on suitable substrates is a promising method for the synthesis of new transition metal oxyhydrides.
Authors:
 [1] ; ;  [1] ;  [2] ; ; ;  [3] ;  [4] ;  [5] ;  [1] ;  [2] ;  [6]
  1. Department of Chemistry, The University of Tokyo, Tokyo 113-0033 (Japan)
  2. (JST), Tokyo 113-0033 (Japan)
  3. Institute for Solid State Physics, The University of Tokyo, Chiba 277-8581 (Japan)
  4. CREST, Japan Science and Technology Agency (JST), Tokyo 113-0033 (Japan)
  5. (Japan)
  6. (KAST), Kawasaki 213-0012 (Japan)
Publication Date:
OSTI Identifier:
22492144
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 5; Journal Issue: 10; Other Information: (c) 2015 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ABSORPTION SPECTROSCOPY; ANIONS; CALCIUM HYDRIDES; CATIONS; CHEMICAL ANALYSIS; COBALT OXIDES; DOPED MATERIALS; ENERGY GAP; EPITAXY; FABRICATION; HYDROXIDES; PEROVSKITE; STABILIZATION; STRONTIUM COMPOUNDS; SUBSTRATES; SYNTHESIS; THIN FILMS; TWO-DIMENSIONAL SYSTEMS; X-RAY SPECTROSCOPY