Spin freezing and slow magnetization dynamics in geometrically frustrated magnetic molecules with exchange disorder

TitleSpin freezing and slow magnetization dynamics in geometrically frustrated magnetic molecules with exchange disorder
Publication TypeJournal Article
Year of Publication2010
AuthorsSchroder C, Fang X, Furukawa Y, Luban M, Prozorov R, Borsa F, Kumagai K
Journal TitleJournal of Physics-Condensed Matter
Volume22
Pages216007
Date Published06/01
ISBN Number0953-8984
Accession NumberISI:000277344500017
KeywordsANTIFERROMAGNET, cluster, state
Abstract

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 behaviour. Also we suggest that our low temperature and low magnetic field nuclear magnetic resonance (NMR) measurements on {Mo72Fe30}, showing rapid and strong broadening of the proton line width on cooling below 600 mK, are evidence for a crossover from paramagnetic behaviour to a frozen spin configuration. Similar broadening is observed in {Mo72Cr30}. This observed effect is consistent with our theory of spin freezing and slow magnetization dynamics in these systems due to exchange disorder.

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