Switching of molecular magnets

In this paper we consider magnetic properties of single-molecule magnets (SMMs). The main focus, however, is on possible mechanisms of magnetic switching of SMMs. One mechanism considered is the phenomenon of macroscopic quantum tunneling of magnetization (QTM) in an external time-dependent magnetic field. When the molecule is additionally attached to magnetic leads, the phenomenon of QTM is associated with transfer of charge and spin between the leads, so the SMM can work as a charge and/or spin pump. Another possibility follows from spin momentum transfer from conduction electrons to the molecule, which effectively may reverse spin moment of the molecule attached to magnetic leads, provided the bias voltage exceeds some threshold value determined by the anisotropy barrier. To calculate the basic transport characteristics we apply the rate equation to a model Hamiltonian that includes exchange interaction of tunneling electrons with the molecule's magnetic core and electron correlations in the LUMO level. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim