Multiple magnetization reversal channels observed in a 3d-4f Single Molecule Magnet

Abstract

The present study discusses the magnetic dynamics of a previously reported cyanide bridged 3d-4f dinuclear DyIIICoIII complex. Following the axial anisotropy suggested by previous Electron Paramagnetic Resonance spectroscopy (EPR) analysis, the complex turned out to show slow relaxation of the magnetization at cryogenic temperature, and this was studied in different temperature and field regimes. The existence of multichannel relaxation pathways that reverse the magnetization was clearly disclosed: a tentative analysis suggested that these channels can be triggered and controlled as a function of applied static magnetic field and temperature. Persistent evidence of a temperature independent process even at higher fields, attributable to quantum tunneling, is discussed, while the temperature dependent dynamics is apparently governed by an Orbach process. The broad distribution of relaxation rates evidenced by the ac susceptibility measurements suggest a relevant role of the intermolecular interactions in this system.