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TT: Fachverband Tiefe Temperaturen

TT 50: Correlated Electrons: Frustrated Magnets - Low-Dimensional Systems

TT 50.9: Vortrag

Mittwoch, 22. März 2017, 17:15–17:30, HSZ 304

Structural and Magnetic Properties of the trirutile-type 1D Heisenberg Antiferromagnet CuTa₂O₆ — •Aleksandr Golubev¹, R. E. Dinnebier¹, A. Schulz¹, R. K. Kremer¹, H. Langbein², A. Senyshyn³, J. M. Law⁴, Th. Hansen⁵, E. E. Gordon⁶, and M.-H. Whangbo⁶ — ¹MPI for Solid State Research, D-70569 Stuttgart, Germany — ²Institut für Anorganische Chemie der TUD, D-01062 Dresden, Germany — ³Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), TUM, D-85747 Garching, Germany — ⁴Dresden High Magnetic Field Laboratory (HLD), D-01314 Dresden-Rossendorf, Germany — ⁵ILL, B.P. 156, 38043 Grenoble, France — ⁶Department of Chemistry, NCSU, Raleigh, North Carolina 27695-8204, USA

Polycrystalline samples of CuTa₂O₆ prepared by low-temperature decomposition of Cu-Ta-oxalate precursors at room temperature crystallize with a monoclinically distorted trirutile structure type. By detailed high temperature x-ray and neutron powder diffraction studies we detected a structural phase transition to the tetragonal trirutile structure-type at 503(3) K. The structural phase transition was ascertained by Raman scattering. GGA+U DFT calculations of the spin exchange parameters, magnetic susceptibility and isothermal magnetization measurements constitute CuTa₂O₆ as new 1D Heisenberg chain with predominant afm nearest neighbor exchange interaction J_nn ≈ 50 K. Heat capacity and low temperature high intensity neutron powder diffraction studies could not find long range order down to 0.4K.