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 interactions at the metal-molecule interfaces. The magnetoresistance of a Fe$|$bilayer-C${}_{70}|$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 modeled in terms of prominent spin-dependent Fe$|$${\text{C}}_{70}$ interface states close to the Fermi level, unfolding the potential of spinterface science to control and optimize spin currents.

• Received 26 August 2013
• Revised 26 February 2014

DOI:https://doi.org/10.1103/PhysRevB.89.115407