Berlin 2008 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 2: Towards Molecular Spintronics
DS 2.5: Vortrag
Montag, 25. Februar 2008, 13:30–13:45, H 2013
A first-principles DFT study of magnetic properties of a series of complexes based on a hexaaza-dithiophenolate ligand — •Claudia Loose1, Eliseo Ruiz2, Berthold Kersting3, and Jens Kortus1 — 1Institut für Theoretische Physik, TU Bergakademie Freiberg, Leipziger Str. 23, D-09599 Freiberg, Germany — 2Departament de Quimica Inorgánica and Institut de Recerca de Quimica Teórica i Computacional, Universitat de Barcelona, Diagonal 647,08028 Barcelona, Spain — 3Institut für Anorganische Chemie, Universität Leipzig, Johannisallee 29, D-04103 Leipzig, Germany
We studied a series of complexes based on a hexaaza-dithiophenolate ligand by first-principles DFT as implemented in the all-electron NRLMOL code. The main focus of our work was on the effect of different bridges and different metal centers on the magnetic exchange coupling. In agreement with experimental results we predict correctly ferromagnetic or antiferromagnetic coupling depending on bridge or metal center. Only in the case of Ni2+-ions we find ferromagnetic coupling. The use of other metal centers results in a strong antiferromagnetic coupling.
Interestingly, the ferromagnetic coupling in case of Ni2+ complexes can be tuned by changing the third bridging ligand. Depending on the bridge the magnetic coupling can be changed between strong antiferromagnetic to strong ferromagnetic coupling. This behavior can be understood within the framework of the Hay-Thibeault-Hoffmann model, which relates the energies of the magnetic orbitals to the magnetic exchange coupling.