Regensburg 2016 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 42: Correlated Electrons: Frustrated Magnets - Cu-based Systems & FeCr
TT 42.7: Talk
Wednesday, March 9, 2016, 11:00–11:15, H18
Interplay of magnetic sublattices in langite Cu4(OH)6SO4· 2H2O — •Satoshi Nishimoto1,2, Stefan Lebernegg3, Alexander A. Tsirlin4, Oleg Janson5, Günther J. Redhammer6, Stefan-Ludwig Drechsler1, and Helge Rosner3 — 1IFW Dresden, Dresden, Germany — 2TU Dresden, Dresden, Germany — 3MPI CPfS, Dresden, Germany — 4Institute of Physics, University of Augsburg, Germany — 5Institute of Solid State Physics, TU Vienna, Austria — 6University Salzburg, Austria
Magnetic and crystallographic properties of the mineral langite Cu4(OH)6SO4· 2H2O are reported. Density-functional band structure calculations suggest a quasi-two-dimensional spin model consisting of two interacting subsystems: (A) Frustrated Heisenberg chains with ferromagnetic nearest-neighbor (NN) and antiferromagnetic (AFM) next-nearest-neighbor (NNN) exchange couplings, which is responsible for the magnetic ordering at TN≃ 5.7 K, and (B) weakly-coupled frustrated chains with AFM NN and NNN exchange couplings. At low temperature, the magnetic susceptibility of the former subsystem is about five times larger than that of the latter one. Therefore, the system can be regarded as a combination of isolated subsystems with respect to applied magnetic field. The subsystem (A) may give an ideal host exhibiting multipolar physics. Experimentally observed magnetic susceptibility, specific heat, and magnetization are also compared to our numerical results.