Orientation-Dependent Structural Phase Diagrams and Dielectric Properties of PbZr1-xTixO3 Polydomain Thin Films
Journal Article - Open Access
University of California - Berkeley Berkeley United States
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The orientation-dependent equilibrium ferroelectric domain structures and dielectric properties of polydomain PbZr1xTixO3 thin films are investigated using a phenomenological Ginzburg-Landau-Devonshire thermodynamic model. We develop and describe three-dimensional polydomain models for 001-, 101-, and 111-oriented films and explore the evolution of the structure and dielectric permittivity of the system as a function of epitaxial strain across the composition range 0.5x1.0. Our studies reveal that the film orientation, epitaxial strain, and composition can combine in unexpected ways to drive exotic phase stability and transformations which have intriguing implications for the properties. In particular, in 101- and 111-oriented films, the application of epitaxial strains along non-001-type crystallographic directions significantly reduces the stability range of the parent tetragonal phase which is dominant in 001-oriented films and results in a variety of new symmetries. We also observe that the film orientation can be used to tune the relative fraction of intrinsic i.e., within a domain and extrinsic i.e., from domain wall motion contributions to the dielectric permittivity. Ultimately these studies reveal how composition, epitaxial strain, and film orientation provide for comprehensive control of the structure and properties of ferroelectrics.
- Electricity and Magnetism