Berlin 2008 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 13: Correlated Electrons: Low-dimensional Systems - Materials 1
TT 13.8: Vortrag
Dienstag, 26. Februar 2008, 11:30–11:45, H 2053
Magnetic measurements on a metal-organic spin-1/2 dimer system – a possible candidate for a 2D field-induced phase transition — •Ulrich Tutsch1, Bernd Wolf1, Michael Lang1, Tonia Kretz2, Hans-Wolfram Lerner2, Matthias Wagner2, Stefan Wessel3, Tanusri Saha-Dasgupta4, Harald Jeschke5, and Roser Valenti5 — 1Physikalisches Institut, J.W. Goethe-Universität, SFB/TR49, D-60438 Frankfurt(M), Germany — 2Institut für Anorganische Chemie, J.W. Goethe-Universität, SFB/TR49, D-60438 Frankfurt(M), Germany — 3Institut für Theoretische Physik III, Universität Stuttgart, D-70550 Stuttgart, Germany — 4S.N. Bose National Centre for Basic Sciences, Salt Lake City, Kolkata 700098, India — 5Institut für Theoretische Physik, J.W. Goethe-Universität, SFB/TR49, D-60438 Frankfurt(M), Germany
We present new data for the low-temperature (T<1K) susceptibility of C36H48Cu2F6N8O12S2 (TK91) as function of the magnetic field. In this material Cu2+ ions form spin-1/2 dimers with an intradimer exchange interaction of J1/kB≈10K mediated by a hydroquinone-derived linker. Previous studies have revealed a weak interdimer coupling J2/kB∼1K. Density Functional Theory calculations support these findings and furthermore indicate a quasi 2-dimensional structure of the interdimer coupling. Therefore, we compare the new susceptibility data with Quantum Monte Carlo Simulations for 2-dimensionally coupled dimers. The results indicate that this material is a candidate for a 2D field-induced phase transition.