From spin-polarized interfaces to giant magnetoresistance in organic spin valves

We calculate the spin-polarized electronic transport through a molecular bilayer spin valve from first principles, and establish the link between the magnetoresistance and the spin-dependent inter- actions at the metal-molecule interfaces. The magnetoresistance of a Fe|bilayer-C70|Fe spin valve attains a high value of 70% in the linear response regime, but it drops sharply as a function of the applied bias. The current polarization has a value of 80% in linear response, and also decreases as a function of bias. Both these trends can be modelled in terms of prominent spin-dependent Fe|C70 interface states close to the Fermi level, unfolding the potential of spinterface science to control and optimize spin currents.