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TT: Tiefe Temperaturen

TT 25: Correlated Electrons - Poster Session

TT 25.63: Poster

Mittwoch, 29. März 2006, 14:30–18:30, P1

Spin-phonon coupling in Cr-based thiospinel systems probed by infrared spectroscopy — •Torsten Rudolf¹, Joachim Hemberger¹, Peter Lunkenheimer¹, Franz Mayr¹, Andrei Pimenov¹, Vladimir Tsurkan^1,2, and Alois Loidl¹ — ¹Center for Electronic Correlation and Magnetism, University of Augsburg, 86159 Augsburg, Germany — ²Institute of Applied Physics, Academy of Sciences of Moldova, 2028 Chisinau, Republic of Moldova

We investigated several Cr-based thiospinels ACr₂S₄ with A=Mn, Fe, Zn, Cd, and Hg. In these magnetic semiconductors interesting physical features were found as e.g. relaxor ferroelectricity and colossal magnetocapacitance [1] in CdCr₂S₄, colossal magnetoresistance in Fe_1−xCu_xCr₂S₄ or an orbital glass state in FeCr₂S₄ [2]. Beside the magnetic and thermodynamic properties we focus on the interplay between magnetism and phonon properties. We systematically studied the temperature and magnetic field dependence of the phonon spectra employing Fourier Transform Infrared Spectroscopy in a range from 5 K to 300 K and in fields of up to 7 T.

[1] J. Hemberger et al., Nature 434, 364 (2005)

[2] R. Fichtl et al., Phys. Rev. Lett. 94, 027601 (2005)