Reversible Changes in Resistance of Perovskite Nickelate NdNiO3 Thin Films Induced by Fluorine Substitution

Tomoya Onozuka, Akira Chikamatsu, Tsukasa Katayama, Yasushi Hirose, Isao Harayama, Daiichiro Sekiba, Eiji Ikenaga, Makoto Minohara, Hiroshi Kumigashira, Tetsuya Hasegawa

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Perovskite nickel oxides are of fundamental as well as technological interest because they show large resistance modulation associated with phase transition as a function of the temperature and chemical composition. Here, the effects of fluorine doping in perovskite nickelate NdNiO3 epitaxial thin films are investigated through a low-temperature reaction with polyvinylidene fluoride as the fluorine source. The fluorine content in the fluorinated NdNiO3-xFx films is controlled with precision by varying the reaction time. The fully fluorinated film (x ≈ 1) is highly insulating and has a bandgap of 2.1 eV, in contrast to NdNiO3, which exhibits metallic transport properties. Hard X-ray photoelectron and soft X-ray absorption spectroscopies reveal the suppression of the density of states at the Fermi level as well as the reduction of nickel ions (valence state changes from +3 to +2) after fluorination, suggesting that the strong Coulombic repulsion in the Ni 3d orbitals associated with the fluorine substitution drives the metal-to-insulator transition. In addition, the resistivity of the fluorinated films recovers to the original value for NdNiO3 after annealing in an oxygen atmosphere. By application of the reversible fluorination process to transition-metal oxides, the search for resistance-switching materials could be accelerated.

Original languageEnglish
Pages (from-to)10882-10887
Number of pages6
JournalACS Applied Materials and Interfaces
Volume9
Issue number12
DOIs
Publication statusPublished - 2017 Mar 29
Externally publishedYes

Keywords

  • electronic structures
  • oxyfluorides
  • pulsed-laser depositions
  • resistance modulations
  • topotactic reactions

ASJC Scopus subject areas

  • Materials Science(all)

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  • Cite this

    Onozuka, T., Chikamatsu, A., Katayama, T., Hirose, Y., Harayama, I., Sekiba, D., Ikenaga, E., Minohara, M., Kumigashira, H., & Hasegawa, T. (2017). Reversible Changes in Resistance of Perovskite Nickelate NdNiO3 Thin Films Induced by Fluorine Substitution. ACS Applied Materials and Interfaces, 9(12), 10882-10887. https://doi.org/10.1021/acsami.7b00855