Berlin 2005 – wissenschaftliches Programm

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MA: Magnetismus

MA 10: FV-internes Symposium "Molecular Magnetism" (Organizer: H.J. Krüger)

MA 10.6: Hauptvortrag

Samstag, 5. März 2005, 11:30–12:00, TU H1012

Rational Design of Single-Molecule Magnets — •Thorsten Glaser — Institut für Anorganische und Analytische Chemie der Westfälischen Wilhelms-Universität Münster, Wilhelm-Klemm-Str. 8, 48149 Münster

Single-molecule magnets are molecules that exhibit a magnetic bistability of pure molecular origin due to a slow relaxation of the magnetization. Thus, information can be stored in a single molecule with dimensions below 5 nm. The necessary prerequisites are a high spin ground state S along with a strong magnetic anisotropy of the easy-axes type which is described by a negative zero-field splitting D. We have started a program to obtain high spin ground states by ferromagnetic interactions between transition metal ions in polynuclear complexes. In order to control the coupling of the transition metal ions we perform a ligand design based on the principles of double exchange, orthogonality of the magnetic orbitals and spin-polarization. Magnetic anisotropy is introduced by enforcing a strong tetragonal ligand field on the transition metal ions. We have successfully synthesized two heptanuclear transition metal complexes with high spin ground states and magnetic anisotropy: Mn6Cr with S = 21/2 and Fe6Cr with S = 27/2. Their magnetic properties and single-molecule magnet behavior will be presented.