Presence of a purely tetragonal phase in ultrathin BiFeO3 films: Thermodynamics and phase-field simulations

Yang Zhang, Fei Xue, Zuhuang Chen, Jun Ming Liu, Long Qing Chen

Research output: Contribution to journalArticle

Abstract

The stability of a purely tetragonal phase relative to the nominal rhombohedral phase in ultrathin BiFeO3 films is investigated using thermodynamics and phase-field simulations. The thermodynamic analysis demonstrates the possible presence of a purely tetragonal state primarily due to the interfacial effect from the constraint of the adjacent layer although the built-in potential and compressive in-plane strain also play a role. Phase-field simulations of the corresponding ultrathin films reveal the coexistence of tetragonal and rhombohedral phases at certain film thickness arising from strain phase separation. It is shown that the piezoelectric coefficient d33 of the two-phase mixture is up to 200% higher than that of the rhombohedral single phase.

Original languageEnglish (US)
Pages (from-to)110-117
Number of pages8
JournalActa Materialia
Volume183
DOIs
StatePublished - Jan 15 2020

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All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

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