Berlin 2012 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 45: Correlated Electrons: Poster Session
TT 45.64: Poster
Donnerstag, 29. März 2012, 15:00–19:00, Poster B
Magnetic ordering transitions of the effective XY-spin-1/2 compound Cs2CoCl4 in transverse magnetic fields — •Oliver Breunig1, Eran Sela2, Benjamin Buldmann2, Markus Garst2, Petra Becker3, Ladislav Bohatý3, Christian Dax1, Ralf Müller1, and Thomas Lorenz1 — 1II. Physikalisches Institut, Universität zu Köln — 2Institut für Theoretische Physik, Universität zu Köln — 3Institut für Kristallographie, Universität zu Köln
Cs2CoCl4 is a model system for studying the magnetism of one-dimensional spin chains. It contains CoCl4 tetrahedra, which form one-dimensional chains along the crystallographic b axis. The orbital groundstate of Co2+ is split by the crystal field into doublets and an easy-plane anisotropy of the magnetization is established. The ground-state doublet is separated from the first excited doublet state by approximately 15 K, such that at temperatures between 0.3 and 4 K the compound is well described by the one-dimensional XXZ model. Decreasing temperature further, magnetic order arises at field-dependent temperatures TC(H). According to [1] spins are confined to the bc-plane in the ordered phase. Measuring thermal expansion with a magnetic field applied along the crystallographic b-axis, we observe a series of magnetic transitions within the ordered state. We discuss thermodynamic properties of the magnetically ordered state.
This work was supported by the DFG through SFB 608.
M. Kenzelmann et al., Phys. Rev. B 65 (2002).