  The zero bias conductance of quantum dots coupled to ferromagnetic leads is
investigated. In the strong coupling regime, it is found that the conductance
is a non-monotonic function of the angle between the magnetisation directions
in the two contacts. This behaviour is an effect of the presence of the leads
which induces an angle dependent spin split of the quantum dot states, and spin
flip transitions between the quantum dot states whenever the magnetisation
directions of the leads are non-collinear which enhances the current density at
the chemical potential. In the weak coupling regime, the system reverts to
normal spin valve character.
