Dresden 2011 – wissenschaftliches Programm

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KR: Fachgruppe Kristallographie

KR 1: Multiferroics I (Joint Session of MA, DF, DS, KR, TT)

KR 1.7: Vortrag

Montag, 14. März 2011, 16:15–16:30, HSZ 04

Optical Spectroscopy on the triangular antiferromagnet CuCrO₂ — •Michael Schmidt, Zhe Wang, Franz Mayr, Vladimir Tsurkan, Joachim Deisenhofer, and Alois Loidl — Experimental Physics 5, Center for Electronic Correlations and Magnetism, Institute of physics, Augsburg University, Germany

CuCrO₂ belongs to the class of triangular lattice antiferromagnets and shows ferroelectricity below T_FE ≈ 24 K [1] while the spins order in a proper screw [2]. Already a moderate magnetic field of 5.3 T can flop the plane of the spins and the polarization. A microscopic theory [3] explains this by the variation of the spin-orbit coupling with the metal-ligand (d-p) hybridization. Recently, electromagnons (magnetic excitations excited by electric field) have been detected in the related compound Cu(Fe,Al)O₂ [4] in the submillimeter range. We report on the optical excitation spectrum of CuCrO₂ including phonons, crystal-field excitations and magnon sidebands. The relation of magnon lifetime with the possible formation of Z₂ vortices in this system is discussed.
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