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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 15: Multiferroics and Magnetoelectric Coupling (joint session MA/KFM)
KFM 15.11: Talk
Wednesday, March 20, 2024, 17:45–18:00, EB 407
Imaging the antiferromagnetic domains in LiCoPO4 via the optical magnetoelectric effect — •Boglárka Tóth1, Vilmos Kocsis2,3, and Sándor Bordács1,4 — 1Department of Physics, Institute of Physics, Budapest University of Technology and Economics, Hungary — 2RIKEN Center for Emergent Matter Science (CEMS), Japan — 3Institut für Festkörperforschung, Leibniz IFW-Dresden, Germany — 4ELKH-BME Condensed Matter Research Group, Budapest University of Technology and Economics, Hungary
LiCoPO4 is a widely researched compound. Not only it is a very promising candidate as a cathode material for lithium-ion batteries, but also shows strong linear magnetoelectric (ME) effect. Its two sublattice antiferromagnetic (AFM) order emerging below TN = 21.7 K breaks spatial inversion and time-reversal symmetries, and correspondingly gives rise to the ME effect. We investigated the optical ME effect of LiCoPO4, which manifests in the so-called directional dichroism; the light absorption difference for counter propagating beams. The absorption of polarized light in the sample was measured after poling, i.e., field-cooling the sample across TN in external E and B fields simultaneously, to stabilize one or the other AFM domain. There is a finite absorption difference for the two AFM domains, which, considering they are time-reversal pairs of each other, we interpret as directional dichroism. A simple transmission microscope setup was constructed to image the AFM domains based on their absorption difference.
Keywords: nonreciprocal directional dichroism; domain imaging; infrared spectroscopy; antiferromagnetism; magnetoelectric coupling