Multiple relaxation times in single-molecule magnets

摘要

Multiple relaxation times detected in the ac magnetic susceptibility of several single-molecule magnets havebeen always assigned to extrinsic factors, such as nonequivalent magnetic centers or effects of intermolecularinteractions in the crystal. By solving quantum relaxation equations, we prove that the observed multiple relaxationtimes can be of intramolecular origin and can show up even in single-ion metal complexes. For the latter aremarkably good description of the coexistent two relaxation times is demonstrated on several experimentalexamples. This proves the relevance of the intramolecular mechanism of multiple relaxation times in suchsystems, which is even easier justified in polynuclear magnetic complexes.