Regensburg 2016 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 42: Correlated Electrons: Frustrated Magnets - Cu-based Systems & FeCr
TT 42.12: Vortrag
Mittwoch, 9. März 2016, 12:30–12:45, H18
Thermodynamic investigations of the quasi-2d triangular Heisenberg antiferromagnet Cs2CuCl4−xBrx (x = 1, 2) — •Ulrich Tutsch, Lars Postulka, Bernd Wolf, Michael Lang, Natalija van Well, Franz Ritter, Cornelius Krellner, and Wolf Assmus — Physikalisches Institut, Goethe-Universität Frankfurt (M), SFB/TR 49
Cs2CuCl4−xBrx (0≤ x≤ 4) is a quasi-two-dimensional Heisenberg antiferromagnet with an anisotropic triangular in-plane coupling of the spins. The ratio J′/J of the spin-spin coupling constants determines the degree of frustration in the system and has been found to be 0.34 (x = 0) and 0.47 (x = 4) for the border compounds. In ref. [1] it has been suggested that for some intermediate Br concentration an even higher degree of frustration can be reached, and indeed, some results pointing into this direction have been reported by Ono et al. [2].
Here, we present specific heat C and susceptibility χ measurements below 1 K in magnetic fields B up to 13.5 T for the intermediate compounds Cs2CuCl2Br2 and Cs2CuCl3Br, which, due to site-selective substitution [1], show a well-ordered halide sublattice. Our results, which point to a relatively high degree of frustration for x = 2, as well as the derived B-T phase diagram will be discussed in the framework of the triangular spin lattice.
0mm [1] P.T. Cong et al., Phys. Rev. B 83, 064425 (2011)
[2] T. Ono et al., J. Phys. Soc. Jpn. 74 Suppl., 135 (2005)