Dresden 2017 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 20: Bio- and Molecular Magnetism
MA 20.2: Vortrag
Dienstag, 21. März 2017, 09:45–10:00, HSZ 301
High-frequency electron paramagnetic resonance investigation of transition metal complexes – Ni monomer and Ni2 dimer complexes as single-molecule magnets — •Sven Spachmann1, Changhyun Koo1, Msia Tavhelidse1, Cebrail Pür1, Roland Bischoff2, Manuel Reh2, Hans-Jörg Krüger2, and Rüdiger Klingeler1,3 — 1Kirchhoff Institute for Physics, Heidelberg University, Heidelberg, Germany — 2Faculty of Chemistry, TU Kaiserslautern, Kaiserslautern, Germany — 3Center for Advanced Materials, Heidelberg University, Heidelberg, Germany
The magnetic properties of a Ni(II) monomer and a Ni(II)2 dimer with a negatively charged radical bridge ligand are studied by means of high-frequency electron paramagnetic resonance (HF-EPR). The g-factors and the spin ground states of both complexes are unambiguously determined from the spectra: g = 2.126, S = 5/2 for the dimer, and g = 2.115, S = 1 for the monomer. Significant zero-field splitting and equally separated resonance features in the EPR spectra indicate the magnetic anisotropy of both complexes. Modelling the experimental data by an appropriate spin Hamiltonian reveals an axial-type anisotropy D = 0.85 K for the dimer and a plane-type anisotropy D = 4.52 K for the monomer. The results are compared to similar Ni2 dimer complexes and the contributions of the different radical bridge ligands to the magnetic anisotropy are discussed.