Low-symmetry monoclinic phase stabilized by oxygen octahedra rotations in thin strained EuxSr1-xTiO3 films

Abstract

Using Landau-Ginzburg-Devonshire theory 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. In biaxially tensile strained films, we discover the presence of a low symmetry monoclinic phase with in-plane ferroelectric polarization that is stabilized by antiferrodistortive oxygen octahedra tilts. The monoclinic phase is stable in a wide temperature range, and is characterized by the large number of energetically equivalent polar and structural twin domains, which stimulates easy twinning of the film and thus enhances its effective piezoelectric response. The flexoelectric coupling and rotostriction give rise to additional spontaneous polarization, piezo- and pyro-electricity in the ferroelastic twin boundaries.

23 pages, 5 figures, 1 table, 3 appendices

References in corpus (5)

• Strain gradient induced polarization in SrTiO3 single crystals
• Reversible Control of Magnetic Interactions by Electric Field in a Single Phase Material
• Room temperature surface piezoelectricity in SrTiO3 ceramics via piezoresponse force microscopy
• First-principles prediction of oxygen octahedral rotations in perovskite-structure EuTiO3
• Intrinsic Structural Disorder and the Magnetic Ground State in Bulk EuTiO3