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 18.2: Talk
Tuesday, March 15, 2011, 11:00–11:15, HSZ 04
Rare-earth induced magnetoelectric effect in multiferroic TbMn2O5 — •Naëmi Leo1, Dennis Meier2, Roman V. Pisarev3, Sang-Wook Cheong4, and Manfred Fiebig1 — 1HISKP, Universität Bonn — 2UC Berkeley, USA — 3Ioffe Institute, St. Petersburg — 4Rutgers University, USA
The presence of magnetic frustration and multi-dimensional magnetic order parameters leads to remarkable effects like magnetically induced ferroelectricity. Such a particularly interesting compound is TbMn2O5 due to the associated magnetic-field controllable electric polarization. The gigantic magnetoelectric coupling originates in the presence of three independent ferroelectric contributions, which can be separatedly accessed by optical second harmonic generation (SHG). Two of these contributions are related to the manganese Mn3+ and Mn4+ magnetism. The third one is attributed to the spin arrangement of the Tb3+ sublattice which also mediates the intricate field-dependent cross-coupling. We confirm this model by measurements taken on isostructural YMn2O5 with non-magnetic Y3+ ions.
Also we perform spatially resolved domain topography to show that the magnetic-field induced polarization reversal in TbMn2O5 does not include domain wall motion but is indeed due to a reversal of only one ferroelectric contribution.
This work was supported by the DFG through SFB 608.