A heterophase polydomain structure has been recently discovered in BiFeO<inf>3</inf>epitaxial ferroelectric films, which provides large electromechanical responses. In this work, the formation of such a microstructure is explained by theory of elastic domains. The thermodynamics of the heterophase polydomain microstructure is analyzed to predict the equilibrium volume fraction of domains at different film-substrate lattice misfits. Extrinsic mechanical and piezoelectric properties are discussed for the heterophase polydomains. It is shown that an applied electric field, which increases electrostatic interaction between domains, may lead to dramatic increase of piezo response. The results of this work are in good agreement with experimental data for BiFeO<inf>3</inf>.

2011 MRS Spring Meeting
Carleton University

Roytburd, A.L. (A. L.), Ouyang, J. (J.), Boyerinas, B.M. (B. M.), Bruck, H.A. (H. A.), Slutsker, J. (J.), & Artemev, A. (2012). Elastic heterophase domains in ferroelectric epitaxial films. In Materials Research Society Symposium Proceedings (pp. 43–54). doi:10.1557/opl.2011.1515