Pressure induced phase transition of nanocrystalline and bulk maghemite (γ-Fe2O3) to hematite (α-Fe2O 3)

Hongyang Zhu, Yanzhang Ma, Haibin Yang, Cheng Ji, Dongbin Hou, Lingyun Guo

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19 Scopus citations

Abstract

Phase transition and bulk moduli of bulk and nanocrystalline γ-Fe2O3 were studied using synchrotron X-ray diffraction under high pressure. Contrary to most other nanomaterials, nanocrystalline γ-Fe2O3 begins to transform into α-Fe2O3 at the same pressure as bulk γ-Fe 2O3, which is caused by a special structure of γ-Fe2O3, in which there exist vacancies of crystal. It is believed that phase transition starts from a certain site of vacancy because of the stress concentration at vacancy sites. Compared to bulk material, nanocrystalline γ-Fe2O3 has a larger bulk modulus, which is ascribed to the large ratio of surface to volume.

Original languageEnglish
Pages (from-to)1183-1186
Number of pages4
JournalJournal of Physics and Chemistry of Solids
Volume71
Issue number8
DOIs
StatePublished - Aug 2010

Keywords

  • C. High Pressure
  • C. X-ray diffraction

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