Dresden 2003 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
MA: Magnetismus
MA 14: Poster: Schichten(1-31), Spinabh.Trsp.(32-47), Exch.Bias(48-54), Spindyn.(55-64), Mikromag.(65-76), Partikel(77-88), Oflmag.(89-92), Spinelektr.(93-98), Elektr.Theo.(99-103), Mikromag+PhasÜ+Aniso.(104-122), MagnMat.(123-134), Messm+Mol-Mag.(135-139), Kondo(140-151)
MA 14.137: Poster
Dienstag, 25. März 2003, 15:15–19:15, Zelt
Magnetic correlations in oxalate spin ladders — •H.-H. Klauss1, J. Kreitlow1, A. Wolter1, D. Baabe1, S. Süllow1, A. Bosse1, D. Mienert1, F.J. Litterst1, D-J. Price2, R. Scheuermann3, and A. Amato3 — 1Institut für Metallphysik und Nukleare Festkörperphysik, TU Braunschweig — 2Department of Chemistry, Univ. of Southampton, United Kingdom — 3Paul Scherrer Institut, Villigen, Switzerland
We present studies of the magnetic behaviour in the isostructural spin ladder materials Na2T2(C2O4)3(H2O)2 with T= Co, Fe (J. Chem. Soc., Dalton Trans. 2000, 3566 ). Here the oxalate (C2O4)2− molecule acts as the bridging element in the rungs and legs of the transition metal ladder. We performed susceptibility and magnetization measurements, muon spin relaxation and Moessbauer spectroscopy (Fe system only). The high temperature susceptibility of the Co system can be described by a Curie-Weiss law and an effective moment for high spin S=3/2 Co. The susceptibility shows a pronounced maximum at 21 K. Moessbauer spectroscopy on the Fe compound revealed a temperature dependent electric field gradient (EFG) due to crystal field splitting and prove a Fe(II) S=2 configuration. No magnetic order is found down to 2K. The high temperature susceptibility also shows an effective S=2 magnetic moment of 5.5 µB and a positive Curie-Weiss temperature of 10 K, in the low temperature regime a maximum is found at 24 K. We will also present muon spin relaxation measurements showing a temperature dependent relaxation due to electronic spin fluctuations.