Berlin 2005 – wissenschaftliches Programm
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MA: Magnetismus
MA 10: FV-internes Symposium "Molecular Magnetism" (Organizer: H.J. Krüger)
MA 10.2: Hauptvortrag
Samstag, 5. März 2005, 09:30–10:00, TU H1012
Minimum single-molecule magnets — •P. Müller1, H. Rupp1, R.W. Saalfrank2, and M. Ruben3 — 1Physikalisches Institut III, Universität Erlangen-Nürnberg — 2Institut für Organische Chemie, Universität Erlangen-Nürnberg — 3Institut für Nanotechnologie, FZ Karlsruhe
Even without long-range magnetic order, some molecular crystals show hysteretic magnetization curves at low temperatures. This effect is a single-molecule property caused by a large uniaxial anisotropy combined with a high-spin ground state. This phenomenon has been observed in a class of cluster molecules containing Fe or Mn ions, with Mn12 acetate as a prototype. Until now, the effect is limited to temperatures below 4.2 K. In order to provide strategies for optimizing new systems, it is natural to focus on systems with a small number of metal ions. We present measurements on ferric stars FeFe3L6, where the star-like coupling topology forces a high-spin ground state of the molecule. We conclude our talk with recent results on mononuclear lanthanide-phthalocyanine double-decker molecules, which are promising candidates for higher working temperatures.