Berlin 2012 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 49: Correlated Electrons: Low-dimensional Systems - Materials 4
TT 49.9: Talk
Friday, March 30, 2012, 11:45–12:00, H 3005
(contribution withdrawn)Optical spectroscopy of the Triangular Lattice Antiferromagnets CuCrO2 and α-CaCr2O4 — •Michael Schmidt1, Zhe Wang1, Franz Mayr1, Sandor Toth2,3, Bella Lake2,3, Nazmul Islam2, Vladimir Tsurkan1, Alois Loidl1, and Joachim Deisenhofer1 — 1Experimental Physics V, Center for Electronic Correlations and Magnetism, Institute of Physics, University of Augsburg, D-86135 Augsburg, Germany — 2Helmholtz Zentrum Berlin, Berlin 14109, Germany — 3Institut für Festkörperphysik, Technische Universität Berlin, D-10623 Berlin, Germany
We will compare and discuss our results obtained by optical
spectroscopy on CuCrO2 and α-CaCr2O4. While CuCrO2 is famous for its multiferroicity [1], in α-CaCr2O4 a polarization can only be observed
under the application of electric or magnetic field, despite having a closely related structure [2]. At near infrared and visible light frequencies we observe Cr3+ crystal field absorptions and below TN excitons and
exciton-magnon-transitions appear. The width of these exciton-magnon transitions is analyzed with respect to the existence of Z2 vortices as proposed by Kojima et al. [3].
S. Seki et al., Phys. Rev. Lett. 101, 067240 (2008)
K. Singh et al., Phys. Rev. B 84, 064129 (2011)
N. Kojima et al., J. Phys. Soc. Jpn. 62, 4137 (1993)