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DF: Fachverband Dielektrische Festkörper

DF 17: Ferroics - Domains, Domain Walls and Skyrmions IV

DF 17.7: Vortrag

Donnerstag, 23. März 2017, 11:30–11:45, WIL B321

Nuclear magnetic and electric interactions in multiferroic Ba₂CoGe₂O₇ — •Martina Schädler¹, Titusz Fehér², Norbert Büttgen¹, Vilmos Kocsis², Yoshinori Tokura³, Yasujiro Taguchi³, Alois Loidl¹, and István Kézsmárki² — ¹Center for Electronic Correlations and Magnetism, Institute of Physics, University of Augsburg, Germany — ²Department of Physics, Budapest University of Technology and Economics, Hungary — ³RIKEN Center for Emergent Matter Science, Wako 351-0198, Japan

In the multiferroic compound Ba₂CoGe₂O₇ the electric polarization is induced magnetically by the spin-dependent hybridization mechanism. As a result the polarization arises locally inside the CoO₄ tetrahedra and is dependent on the orientation of the external magnetic field H. Nuclear Magnetic Resonance (NMR) allows access to the local electric field gradient (EFG) via the nuclear quadrupole moment. We performed ⁵⁹Co NMR measurements on Ba₂CoGe₂O₇ for various orientations of the applied field in order to determine the local microscopic properties of magnetic spin order and electric polarization at the cobalt site: (1) we were able to model the local hyperfine field at the two magnetically inequivalent cobalt sites and (2) observed the displacement of the surrounding ions by the NMR quadrupolar effect.