Regensburg 2007 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 2: Quantum-Critical Phenomena
TT 2.3: Vortrag
Montag, 26. März 2007, 10:00–10:15, H19
Low-temperature magnetic properties of novel spin-dimer systems synthesized by bridging Cu(II) ions with modified hydroquinone ligands — •Y Tsui1, U Tutsch1, A Brühl1, K Remović-Langer1, V Pashchenko1, B Wolf1, M Lang1, T Kretz2, H-W Lerner2, M Wagner2, A Salguero3, B Rahaman4, T Saha-Dasgupta4, and R Valentí3 — 1Physikalisches Institut, J.W. Goethe-Universität, Frankfurt, Germany. — 2Institut für Anorganische Chemie, J.W. Goethe-Universität, Frankfurt, Germany. — 3Institut für Theoretische Physik, J.W. Goethe-Universität, Frankfurt, Germany. — 4S.N. Bose Centre, Kolkata, India.
We have recently synthesized novel spin-dimer systems by bridging Cu(II) ions with hydroquinone linkers. By chemically modifying the hydroquinone linkers, spin-dimer systems with different intradimer and interdimer interactions are realized. These compounds include isolated and coupled spin-dimer systems. We will discuss the magnetic properties of these systems at low temperatures. In particular, we will focus on one of the 3D coupled spin-dimer systems, [C36H48Cu2F6N8O12S2] (TK91). Thermodynamic and magnetic measurements on TK91 suggest that a field-induced phase transition takes place at very low temperatures (T 0.2K) and at fields between ∼5.8 and ∼6.5T. Such a phase transition has been observed in other spin-dimer systems and was interpreted as the Bose-Einstein condensation (BEC) of magnons. The ability to tune the magnetic interactions in TK91 will make it possible to explore the BEC phenomenon in magnetic systems under various conditions.