Regensburg 2007 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 31: Bio- and Molecular Magnetism
MA 31.7: Vortrag
Freitag, 30. März 2007, 12:30–12:45, H10
High field level crossing studies on spin dimers in the low dimensional quantum spin system Na2T2(C2O4)3(H2O)2 with T=Ni,Co,Fe,Mn — •Christopher Mennerich1, Hans-Henning Klauss1, Anja Wolter1, Stefan Süllow1, Jochen Litterst1, Christian Golze1, Vladik Kataev2, Rüdiger Klingeler2, Vladik Kataev2, and Daniel Price3 — 1Institut of Condensed Matter Physics, TU Braunschweig, Mendelssohnstr.3, D-38106 Braunschweig, Germany — 2Leibniz-Institute for Solid State and Materials Research IFW Dresden, P.O. Box 270116, D-01171 Dresden, Germany — 3WestCHEM,Department of Chemistry, University of Glasgow, Glasgow, G12 8QQ, UK
We demonstrate the application of high magnetic fields to study the magnetic properties of low dimensional spin systems. We present a case study on the series of 2-leg spin-ladder compounds Na2T2(C2O4)3(H2O)2 with T = Ni, Co, Fe and Mn. In all compounds the transition metal is in the T2+ high spin configuation. The localized spin varies from S=1 to 3/2, 2 and 5/2 within this series. The magnetic properties were examined experimentally by magnetic susceptibility, pulsed high field magnetization and specific heat measurements. The data are analysed using a spin hamiltonian description. Although the transition metal ions form structurally a 2-leg ladder, an isolated dimer model consistently describes the observations very well. All compounds exhibit magnetic field driven ground state changes which at very low temperatures lead to a multistep behaviour in the magnetization curves.