Regensburg 2013 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 45: Magnetic Coupling and Spin Structures
MA 45.8: Vortrag
Donnerstag, 14. März 2013, 17:00–17:15, H10
Spindynamics in CaBaCo2Fe2O7 under strong geometrical frustration — •Johannes Reim1, Lars Fritz2, Martin Valldor3, and Werner Schweika1 — 1JCNS-2 and PGI-4, Forschungszentrum Jülich, 52425 Jülich, Germany — 2Institut für Theoretische Physik, Universität zu Köln, 50937 Köln, Germany — 3II. Physikalisches Institut, Universität zu Köln, 50937 Köln, Germany
Recent studies of spin correlations in materials belonging to the swedenborgite compound family (P63mc)[1] exhibit signs of unusual strong geometric frustration: at low temperatures, indications for quasi 2D spin correlations, spin glass/liquid states, and also rather complex, partly ordered ground states have been observed.[2-3] Several groups have investigated this compound family with different stoichiometry, mainly focusing on solving structural and ground state configurations (f.e. [4]). Since the material characteristics are dominated by the strong magnetic frustration, excitations are very sensitive to small changes in ordering and exchange interactions. We will present neutron inelastic scattering on a single crystal of the compound CaBaCo2Fe2O7, that have been obtained from triple axis (PANDA) and thermal time-of-flight scattering (ARCS). The experimental results will be discussed in comparison with theoretical calculations of the phase diagram and the spin dynamics based on nearest neighbor Heisenberg models.
[1] M. Valldor and M. Andersson. Solid State Sci. 4(7):923-931 (2002)
[2] W. Schweika et al. Phys. Rev. Lett., 98(6):067201 (2007)
[3] D. D. Khalyavin et al. Phys. Rev. B, 82(9):094401 (2010)
A. Huq et al. J. Solid State Chem., 179(4):1136-1145 (2006)