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DF: Fachverband Dielektrische Festkörper

DF 5: Multiferroics 2 (jointly with MA,DS,KR,TT)

DF 5.12: Vortrag

Montag, 11. März 2013, 18:00–18:15, H3

Low-lying magnetic excitations in the distorted triangular lattice antiferromagnet α-CaCr₂O₄ — •Michael Schmidt¹, Zhe Wang¹, Sandor Toth², Bella Lake², A.T.M.Nazmul Islam², 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 für Materialien und Energie, D-14109 Berlin, Germany

We will discuss our results on α-CaCr₂O₄ obtained by FIR and Terahertz spectroscopy. This compound orders below T_N = 42.6 K in a proper screw 120^∘ magnetic order, but shows additional low-lying magnetic modes indicative for the vicinity of a more complex magnetic order [1], [2]. Our spectra obtained by FTIR and THz-TD spectroscopy show several optical magnons appearing below the magnetic ordering with anomalous temperature dependence. We will discuss their polarization dependence and a possible magnetoelastic coupling of these modes.
[1] S. Toth et al., Phys. Rev. B 84, 054452 (2011)

[2] S. Toth et al., PRL 109, 127203 (2012)