Dresden 2011 – scientific programme

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MA: Fachverband Magnetismus

MA 18: Multiferroics IV: Exotic Properties and Dynamics (jointly with DF, DS, KR, TT)

MA 18.3: Talk

Tuesday, March 15, 2011, 11:15–11:30, HSZ 04

Three-dimensional distribution of protected ferroelectric vortices in multiferroic hexagonal YMnO₃ — Tobias Jungk¹, •Martin Lilienblum², Ákos Hoffmann¹, Manfred Fiebig², and Elisabeth Soergel¹ — ¹PI, Universität Bonn, Wegelerstraße 8, 53115 Bonn, Germany — ²HISKP, Universität Bonn, Nussallee 14-16, 53115 Bonn, Germany

Multiferrroics are a rich source for "unusual" forms of ferroelectric order. The spontaneous polarizations is induced by magnetism, charge order, geometric effects, etc., and may lead to novel domain states and functionalities. Here we show by piezoresponse force microscopy that ferroelectric domains in hexagonal multiferroic YMnO₃ form vortex-like structures around the direction of polarization. Although one would intuitively associate the sixfold character of the domain vortices to the uniaxial hexagonal structure, sixfold vortices are also present perpendicular to the direction of the spontaneous polarization. We will explain the intriguing topology on the basis of a simple geometric model. In addition, we will show how individual domain vortices are affected by application of an electric field applied along the polarization axis.