Regensburg 2016 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 48: Poster Session II
MA 48.59: Poster
Donnerstag, 10. März 2016, 15:00–18:00, Poster B1
Hidden Symmetries in the Spin Molecules MgCr2O4, ZnCr2O4, and CdCr2O4 — •Mamoun Hemmida1, Hans-Albrecht Krug von Nidda1, Vladimir Tsurkan1,2, and Alois Loidl1 — 1Experimental Physics V, Center for Electronic Correlations and Magnetism, Institute for Physics, University of Augsburg, Germany — 2Institute of Applied Physics, Academy of Sciences of Moldova, Republic of Moldova
The spin dynamics of frustrated antiferromagnetic (AFM) chromium spinel oxides XCr2O4 (X: Mg, Zn, Cd) is investigated by means of Electron Spin Resonance (ESR) spectroscopy. From the temperature dependent ESR linewidth, an unconventional spin-relaxation behaviour is observed. Similar to the two-dimensional triangular lattice AFMs ACrO2 (A: H, Li, Na, Cu, Ag, Pd), direct spin-spin interactions are dominant. A Berezinskii-Kosterlitz-Thouless-like (BKT) scenario successfully describes the linewidth in the whole paramagnetic Regime.1,2 In order to describe the spin-relaxation via vortex-like excitations in XCr2O4 compounds, generalized BKT model with internal continuous Abelian symmetries is applied.3
1- M. Hemmida et al., Phys. Rev. B 80, 054406 (2009).
2- M. Hemmida et al., J. Phys. Soc. Jpn. 80, 053707 (2011).
3- S. A. Bulgadaev, J. Exp. and Theo. Phys. 89, 1107 (1999).