Dresden 2017 – scientific programme

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MA: Fachverband Magnetismus

MA 20: Bio- and Molecular Magnetism

MA 20.12: Talk

Tuesday, March 21, 2017, 12:30–12:45, HSZ 301

Inelastic Neutron Scattering and Mössbauer Spectra of a Novel Spin Frustrated Fe₇-Propeller — •Siyavash Nekuruh¹, K. Prsa¹, I. Kühne², C.E. Anson², A.K. Powell², and O. Waldmann¹ — ¹Physikalisches Institut, Universität Freiburg, Germany — ²Institut für Anorganische Chemie, Karlsruhe Institut für Technologie (KIT)

Among the series of hepta-nuclear Fe^III molecular complexes with disk shape, the molecule [Fe₇^III(Cl)(MeOH)₆O₃(OMe)₆(PhCO₂)₆]Cl₂, or Fe₇ in short, is exceptional: It exhibits a unique antiferromagnetic exchange topology, which is reminiscent of a three-bladed propeller, giving rise to spin frustration.

We here present a study of the magnetic excitations in Fe₇ by inelastic neutron scattering (INS), and Mössbauer spectroscopy. The INS spectra exhibit three features at energies of 0.27, 0.57 and 1 meV, which from T and Q dependence are of magnetic origin. Field dependent Mössbauer spectra could be fitted to two well defined and distinct sextets, one of the sextets was assigned to the central Fe ion and the other to the six peripheral Fe ions. The Mössbauer data allow us to extract the respective local Fe spin densities, providing additional insight in the spin frustration in the molecule.