Dresden 2009 – scientific programme
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MA: Fachverband Magnetismus
MA 40: Poster II: Bio- and Molecular Magnetism (1-9); Magnetic Coupling Phenomena/Exchange Bias (10-15); Magnetic Particlicles and Clusters (16-29); Micro and Nanostructured Magnetic Materials (30-51); Multiferroics (52-64); Spin Injection in Heterostructures (65-67); Spin-Dyn./Spin-Torque (68-93); Spindependent Transport (94-108)
MA 40.55: Poster
Friday, March 27, 2009, 11:00–14:00, P1A
Topology of the electric order in multiferroic orthorhombic DyMnO3 by SHG spectroscopy — •Tim Günter1, Dennis Meier1, Thomas Lottermoser1, Dimitri Argyriou2, and Manfred Fiebig1 — 1HISKP, University of Bonn, Germany — 2Helmholtz Centre Berlin for Materials and Energy, Germany
Multiferroics where a spontaneous electric polarization forms as a direct consequence of magnetic spiral order are of great interest. However, essential aspects of their ferroicity and the precise nature of the large magnetoelectric effects displayed by these compounds remain unclear. One set of these so-called spin-spiral multiferroics are the perovskite manganites RMnO3 (R=Tb, Dy). Here we report on the investigation of orthorhombic DyMnO3 by second harmonic generation (SHG) spectroscopy and topology. Due to its high absorption in the visible range a detectable SHG signal requires using femtosecond laser pulses in a reflection geometry. Performing SHG polarization analysis based on SHG selection rules allows the separation of crystallographic background and magnetically induced ferroelectric contributions. A clear evidence of the observation of the magnetically induced electric order below ≈ 19 K was given by the temperature dependence and the spectral distribution of the SHG contributions. In addition, first results on the imaging of magnetically induced ferroelectric domains are reported. A detailed investigation of DyMnO3 allows to generalize results gained on other spin-spiral multiferroics displaying magnetically induced ferroelectricity like MnWO4 and TbMn2O5.