  We study transport properties of a single-molecule magnet (SMM) weakly
coupled to one nonmagnetic and one ferromagnetic lead. Using the diagrammatic
technique in real time, we calculate transport in the sequential and
cotunneling regimes for both ferromagnetic and antiferromagnetic exchange
coupling between the molecule's LUMO level and the core spin. We show that the
current flowing through the system is asymmetric with respect to the bias
reversal, being strongly suppressed for particular bias polarizations. Thus,
the considered system presents a prototype of a SMM spin diode. In addition, we
also show that the functionality of such a device can be tuned by changing the
position of the molecule's LUMO level and strongly depends on the type of
exchange interaction.
