Berlin 2015 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 28: Poster Session on Ferroic Domain Walls - Multiferroics (jointly with DF, KR, MA)
TT 28.26: Poster
Monday, March 16, 2015, 19:00–21:00, Poster C
Emergence of ferroelectricity in multiferroic h-YMnO3 — •Martin Lilienblum1, Thomas Lottermoser1, Sebastian Manz1, Sverre M. Selbach2, Andres Cano3, and Manfred Fiebig1 — 1Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland — 2Department of Material Science and Engineering, NTNU, N-7491 Trondheim, Norway — 3CNRS, Université de Bordeaux, ICMCB, UPR 9048, F-33600 Pessac, France
Universal scaling laws, interfacial nano-electronics, and topological defects are currently studied using hexagonal manganites RMnO3 (R= Sc, Y, Dy-Lu) as model system. In spite of the remarkably broad interest in the system, surprisingly little is known about the origin of the ferroelectric state. Here we solve the controversy about the emergence of the spontaneous polarization and its coupling to the underlying structural distortion by applying scanning probe microscopy (SPM) and optical second harmonic generation (SHG). We trace the spontaneous polarization by SHG from 100 K to 1450 K directly and contact-free. We find that only a single transition exists in which the polarization arises slower than expected as by-product of the structural distortion. By thermal treatments close to the structural transition and subsequent SPM scans, we show that the exceptionally robust ferroelectric domain pattern is determined only by the structural distortion. In summary we reveal that the ferroelectric order results from an interplay of electric polarization, topological effects, and temperature.