Anna N. Morozovska, Yijia Gu, Victoria V. Khist, Maya D. Glinchuk, Long-Qing Chen, Venkatraman Gopalan, Eugene A. Eliseev
Using Landau-Ginzburg-Devonshire 2-4-power expansion and phase field modeling we explore the complex interplay between the long-range structural order parameter (oxygen octahedron rotations) and polarization in EuxSr1-xTiO3 thin epitaxial films. The important feature, not reported previously in the bulk incipient ferroelectrics, was found in EuxSr1-xTiO3 thin epitaxial films at tensile misfit strains. Namely the presence of antiferrodistortive octahedra tilts stabilize the low symmetry monoclinic phase with in-plane ferroelectric polarization The monoclinic phase is stable in a wide temperature range and is characterized by the great number of energetically equivalent polar and structural twin domains. This great amount of possible twin pairs stimulates the film easy twinning and thus enhances its effective piezoelectric response. The flexoelectric coupling and rotostriction give rise to additional spontaneous polarization, piezo- and pyro-electricity of the ferroelastic twin boundaries.
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http://arxiv.org/abs/1212.6509
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