Strain-induced isosymmetric phase transition in BiFeO 3

By A. Hatt, N. Spaldin, C. Ederer. 2009

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We calculate the effect of epitaxial strain on the structure and properties of multiferroic bismuth ferrite, ${\text{BiFeO}}_{3}$, using first-principles density-functional theory. We investigate epitaxial strain corresponding to an (001)-oriented substrate and find that, while small strain causes only quantitative changes in behavior from the bulk material, compressive strains of greater than 4% induce an isosymmetric phase transition accompanied by a dramatic change in structure. In striking contrast to the bulk rhombohedral perovskite, the highly strained structure has a $c/a$ ratio of $\ensuremath{\sim}1.3$ and five-coordinated Fe atoms. We predict a rotation of polarization from [111] (bulk) to nearly [001], accompanied by an increase in magnitude of $\ensuremath{\sim}50\mathrm{%}$, and a suppression of the magnetic ordering temperature. Our calculations indicate critical strain values at which the two phases might be expected to coexist and shed light on recent experimental observation of a morphotropic phase boundary in strained ${\text{BiFeO}}_{3}$.

Subfields: Condensed Matter Physics, Electronic, Optical and Magnetic Materials, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/4e5bf794616fc74cd259b429ca95c2de847b7cb2