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KR: Fachgruppe Kristallographie
KR 3: Poster Session on Ferroic Domain Walls - Multiferroics (DF jointly with KR, MA, TT)
KR 3.1: Poster
Monday, March 16, 2015, 19:00–21:00, Poster C
Superdomains in K0.9Na0.1NbO3 thin films on NdScO3 substrates — •Jutta Schwarzkopf1, Martin Schmidbauer1, Dorothee Braun1, Albert Kwasniewski1, Jan Sellmann1, and Michael Hanke2 — 1Leibniz Institute for Crystal Growth, Berlin, Germany — 2Paul- Drude-Institut für Festkörperelektronik, Berlin, Germany
Incorporation of lattice strain in thin films gives rise to the creation of controlled arrays of domains and can lead to very complex domain structures. Understanding of strain induced domain formation will open the possibility to selectively influence film properties. Due to its orthorhombic symmetry (K,Na)NbO3 films offer a large variety of ferroelectric and ferroelastic domain types. In this study K0.9Na0.1NbO3 thin films were grown under slight compressive lattice strain on NdScO3 substrates by MOCVD. Lateral PFM images of the (100) oriented films reveal bundles of ferroelectric domains along the [001] substrate direction and a width of 100-200 nm which are superimposed by ferroelastic domains forming regularly arranged herringbone patterns with a periodicity of 30 nm. The domain walls within the domain bundles are tilted alternatingly by +15∘ and -15∘ with respect to the [110] orientation of the substrate. Grazing incidence x-ray diffraction experiments have shown that adjacent superdomain bands exhibit an in-plane monoclinic lattice distortion of 0.12∘. We conclude that the hierarchical structure leads to a domain formation on two scales, which effectively release the misfit strain in the film induced by the substrate.