Topotactic reductive fluorination of strontium cobalt oxide epitaxial thin films

Tsukasa Katayama, Akira Chikamatsu, Yasushi Hirose, Tomoteru Fukumura, Tetsuya Hasegawa

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)

Abstract

Since the discovery of oxyfluoride cuprate superconductors, many efforts have been made to search for new transition-metal oxyfluoride compounds. Recently, the topotactic fluorination reaction using polyvinylidene fluoride (PVDF) has gained attention because of the low-temperature synthesis of oxyfluorides. In this study, we report the fabrication of SrCoOxFy epitaxial thin films via topotactic fluorination of SrCoO2.5 precursor films with PVDF. X-ray diffraction analysis showed that the SrCoOxFy film, with an anion-vacant perovskite structure, was obtained by fluorination at 150 °C and that the in-plane lattice constant was completely dependent on the substrate. Energy dispersive X-ray spectrometry revealed that the chemical composition of the fluorinated film was SrCoO1.9±0.4F0.5±0.1 and X-ray photoemission spectroscopy showed that the Co ions had a mixed valence state of 2+ and 3+. This valence state was smaller than that in the SrCoO2.5 precursor film, indicating that PVDF acted as a reductive fluorinating agent for the SrCoO2.5 film. Moreover, the SrCoO1.9±0.4F0.5±0.1 film did not exhibit ferromagnetism even at 10 K, suggesting the presence of an antiferromagnetic interaction between the Co ions.

Original languageEnglish
Pages (from-to)527-530
Number of pages4
JournalJournal of Sol-Gel Science and Technology
Volume73
Issue number3
DOIs
Publication statusPublished - 2015 Mar
Externally publishedYes

Keywords

  • Epitaxial thin film
  • Oxyfluorides
  • Pulsed-laser deposition
  • Topotactic reaction
  • Transition-metal compounds

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Chemistry(all)
  • Biomaterials
  • Condensed Matter Physics
  • Materials Chemistry

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