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TT: Fachverband Tiefe Temperaturen
TT 28: Poster Session on Ferroic Domain Walls - Multiferroics (jointly with DF, KR, MA)
TT 28.3: Poster
Monday, March 16, 2015, 19:00–21:00, Poster C
Strain-induced defect-polarization coupling in SrMnO3 films — •Carsten Becher1, Laura Maurel2, Ulrich Aschauer1, Martin Lilienblum1, Cesar Magen2, Dennis Meier1, Eric Langenberg2, Morgan Trassin1, Javier Blasco3, Ingo Krug4, Pedro Algarabel3, Nicola Spaldin1, Jose Pardo2, and Manfred Fiebig1 — 1ETH Zürich, Zürich, Switzerland — 2Instituto de Nanoscienciencia de Aragon, Zaragoza, Spain — 3Departemento der Fisica de la Materia Condensada, Zaragoza, Spain — 4Institut für Optik und Atomare Physik, Berlin, Germany
Epitaxial strain can stabilize new matter phases in thin films and is thus a degree of freedom to increase functionality. Here we demonstrate a novel polar phase in 20 nm SrMnO3 films that are epitaxially grown under tensile strains by pulsed laser deposition. High resolution X-Ray diffraction and transmission electron microscopy confirm the crystalline quality of the tetragonal films. We use nonlinear optics to proof that strain induces polarity, and density functional theory to show that it simultaneously increases the concentration of oxygen vacancies. These vacancies accumulate at the polar domain walls where they establish an electrostatic barrier to electron migration. As a consequence, scanning probe microscopy shows that the electrical conductance is structured into isolated "nanocapacitors" which can be charged individually.