An Empirical Model for Perovskite Tetragonality

Kevin R. Tolman, Rick Ubic

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Tetragonal distortions in perovskites are useful for advanced devices, as they can induce functional properties like capacitance, piezoelectricity, pyroelectricity, and ferroelectricity. These distortions are commonly due to either second-order Jahn-Teller effects or antiferrodistortive instabilities. Accurate empirical composition-structure models can significantly reduce the time and cost involved with developing new functional ceramics; however, until now no such model has existed for tetragonal perovskites, the structures of which are further complicated by extrinsic point defects often used to tune electrical properties. In this work, LeBail refinements of X-ray diffraction patterns obtained from [(Pb y Ba 1−y ) (1−3x) La (2x) ]TiO 3 ( P 4 mm , No. 99) were conducted to measure lattice constants and reveal tetragonality trends. These trends were combined with a model for unit-cell volume in order to derive a general empirical model, based solely on published ionic radii data, for tetragonal lattice constants of perovskites in P 4 mm and P 4/ mmm .

Original languageAmerican English
Pages (from-to)825-835
Number of pages11
JournalJournal of Alloys and Compounds
Volume690
DOIs
StatePublished - 5 Jan 2017

Keywords

  • Modeling
  • Perovskite
  • Tetragonality
  • Vacancies

EGS Disciplines

  • Materials Science and Engineering

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