Monoclinic phases arising across thermal inter-ferroelectric phase transitions

Yijia Gu, Fei Xue, Shiming Lei, Tom T.A. Lummen, Jianjun Wang, Venkatraman Gopalan, Long Qing Chen

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

Thermotropic phase boundaries (TPBs), as thermal analogs of morphotropic phase boundaries (MPBs), are associated with the thermal inter-ferroelectric phase transitions. Similar to an MPB, a TPB exhibits a characteristically flattened energy profile which favors polarization rotation, thus giving rise to a structurally bridging low-symmetry phase. We report on the kinetic process of thermal inter-ferroelectric phase transitions in BaTiO3 and KNbO3 using the phase-field method. The domain structures are found to play key roles in stabilizing the monoclinic phase. In simple domain structures, the monoclinic phase is a transient phase and cannot be stabilized into its neighboring phase regimes. However, by introducing structural inhomogeneity (orthogonal in-plane domain twins), we found that the monoclinic phase can be stabilized over a range of over 100 K across the transition. As a result, the piezoelectric properties are enhanced due to the stabilized monoclinic phase. In addition to the emergence of new piezoelectric components with monoclinic symmetry, most of the original components present in the tetragonal symmetry also show substantial enhancement with the rotation of polarization.

Original languageEnglish (US)
Article number024104
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume90
Issue number2
DOIs
StatePublished - Jul 31 2014

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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