Berlin 2018 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 25: Multiferroics and magnetoelectrics II (joint session MA/KFM)
MA 25.7: Vortrag
Mittwoch, 14. März 2018, 11:15–11:30, EB 202
Magnetic field control of cycloidal domains and electric polarization in multiferroic BiFeO3 — •Sándor Bordács1, Dániel Farkas1, Jonathan White2, Robert Cubitt3, Lisa DeBeer-Schmitt4, Toshimitsu Ito5, and István Kézsmárki1,6 — 1Department of Physics, Budapest University of Technology and Economics and MTA-BME Lendület Magneto-optical Spectroscopy Research Group, Budapest, Hungary — 2Laboratory for Neutron Scattering and Imaging, PSI, Villigen, Switzerland — 3Institut Laue-Langevin, Grenoble, France — 4Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA — 5National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, Japan — 6Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, Augsburg, Germany
The magnetic field induced rearrangement of the cycloidal spin structure in ferroelectric monodomain single crystals of the room-temperature multiferroic BiFeO3 is studied using small-angle neutron scattering (SANS). The cycloid propagation vectors are observed to rotate when magnetic fields applied perpendicular to the rhombohedral (polar) axis exceed a pinning threshold value of ∼5 T. In light of these experimental results, a phenomenological model is proposed that captures the rearrangement of the cycloidal domains, and we revisit the microscopic origin of the magnetoelectric effect. A new coupling between the magnetic anisotropy and the polarization is proposed that explains the recently discovered magnetoelectric polarization to the rhombohedral axis.