Berlin 2008 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 13: Correlated Electrons: Low-dimensional Systems - Materials 1

TT 13.9: Vortrag

Dienstag, 26. Februar 2008, 11:45–12:00, H 2053

Magnetic properties of the spin-1/2 chain material (6MAP)CuCl₃ — •M. Ozerov¹, E. Čižmár¹, S. Zvyagin¹, C. Landee², M. Turnbull², and J. Wosnitza¹ — ¹Hochfeld-Magnetlabor Dresden (HLD), Forschungszentrum Dresden - Rossendorf, Germany — ²Clark University, Worcester, MA, USA

Recently, low-dimensional spin systems have received a considerable amount of attention due to their relevance to numerous quantum phenomena such as quantum criticality problems, spin-Peierls transitions, etc. Here we report on magnetization, electron paramagnetic resonance (EPR) and specific-heat measurements of the spin-1/2 Heisenberg antiferromagnetic chain material (6MAP)CuCl₃. Magnetization data measured at 0.1 T exhibit a maximum at about 70 K, indicating the low-dimensional character of the magnetic interactions. The data are in a good agreement with the temperature dependence of the resonance peak intensity measured at 73 GHz. At low temperatures (T < 25 K) the EPR linewidth drastically increases, indicating a possible enhancement of 3D short-range-order correlations. Such behavior is consistent with a broad maximum in the specific heat observed at about 1.5 K, which can be interpreted in terms of 3D magnetic ordering. In addition, we present results of room-temperature X-band EPR measurements of (6MAP)CuCl₃, including angular dependence of the g-factor and of the resonance linewidth.
The work was supported in part by the DFG through Grant No. ZV 6/1-1.