Quantum tunneling of magnetization via well-defined Dy-Cu exchange coupling in a ferrimagnetic high-spin [Dy4Cu] single-molecule magnet

A centrosymmetric rectangular complex [DY4Cu] was prepared from dysprosium(III) 1,1,1,5,5,5-hexafluoropentane-2,4-dionate and copper(II) dimethylglyoximate. From magnetic studies, the Dy magnetic moments are all aligned parallel at the ground state via anti-ferromagnetic superexchange interaction with the central Cu spin. In pulsed-field magnetization measurements at 0.5 K, complex [DY4Cu] exhibited magnetization steps with hysteresis, which is typical of a single-molecule magnet. This behavior is explained in terms of a simple Ising model together with well-defined Dy-Cu exchange coupling (-0.64 K). (C) 2007 Elsevier B.V. All rights reserved.