Regensburg 2007 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 31: Bio- and Molecular Magnetism
MA 31.4: Vortrag
Freitag, 30. März 2007, 11:45–12:00, H10
Magnetic properties of organometallic complexes studied by XMCD — •Paolo Imperia1, Maria Benedetta Casu2, Michael Martins1, and Thomas Chassé2 — 1Universität Hamburg, Institut für Experimentalphysik, Luruper Chaussee 149, 22761 Hamburg — 2Universität Tübingen, Institut für Physikalische und Theoretische Chemie, Auf der Morgenstelle 8, 72076 Tübingen
The magnetic properties of molecular based magnets can be tuned playing with the constituent blocks and growing parameters. Strategies used to achieve high magnetic moments imply the correct positioning of electronegative atoms, like oxygen and nitrogen, leading to large occupation probability by an unpaired electron, simultaneously achieving intermolecular magnetic order without destroying the intramolecular properties. To understand their magnetic properties the knowledge of the internal magnetic structure is of paramount importance and the key question, which element in the compound shows magnetic ordering and which orbital acquires a magnetic moment, needs to be answered. Absorption spectroscopy with its elemental specificity can help in resolving such problem. Here, we present and discuss first results of x-ray magnetic circular dichroism (XMCD) measurements done at the Mn and Ni L2,3 edges and N K edge of a selection of organic stable compounds like manganese tricyanomethanide (Mn[C(CN)3]2) which due to the tridentate nature of the C(CN)3 forms a triangular lattice and exhibits magnetic frustration, and MnNi(NO2)4(en)2 (en = ethylendiamine), a bimetallic chain compound where the ferromagnetically coupled Mn and Ni ions linked by NO2 molecules alternate.