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MA: Fachverband Magnetismus

MA 11: Magnetic Materials

MA 11.3: Vortrag

Montag, 23. März 2009, 15:45–16:00, HSZ 103

Spin freezing and slow magnetization dynamics in geometrically frustrated magnetic molecules with exchange disorder — •Christian Schröder^1,2, Yuji Furukawa², Marshall Luban², Ruslan Prozorov², and Ferdinando Borsa^2,3 — ¹Department of Engineering and Mathematics, University of Applied Sciences Bielefeld, D-33602 Bielefeld, Germany — ²Ames Laboratory & Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA — ³Dipartimento di Fisica “Alessandro Volta”, Università di Pavia, I-27100 Pavia, Italy

We show that intramolecular exchange disorder recently found in the geometrically frustrated magnetic molecules {Mo₇₂Fe₃₀} and {Mo₇₂Cr₃₀} leads in a classical Heisenberg model description to spin freezing and slow magnetization dynamics reminiscent of spin glass behavior. Our low temperature and low magnetic field NMR measurements on these molecules are explained as a cross-over of the proton line width from paramagnetic behavior to a frozen spin configuration at about 400 mK.