Electric and Photovoltaic Switching by Ionic Migration with a Magnetic Record

Combining optical and magnetic functionalities into memristors is an attractive option to expand applications into image recognition, information storage, and low power processing. Here, we have fabricated ferromagnetic-fullerene-manganese oxide structures that display a hysteretic, nonlinear I-V characteristic and a photovoltaic effect with a photocurrent dependent on the relative alignment of the magnetization and the light polarization vector. Reversible, voltage-induced oxygen migration from manganese oxide into the molecular layer reduces the resistivity of the device by several orders of magnitude, eliminates the nonlinear transport, and quenches the photovoltaic response, giving rise to an optically sensitive memristor where the photocurrent is dependent on both the electrical and magnetic history of the device. Density functional theory calculations attribute the origin of these effects to changes in the electronic structure at the Fermi level and a reduction of the interface dipole upon ionic migration. These results open research pathways towards single-molecule scale memristive memories with optical excitation, electrical readout and magnetic sensing functionalities.