Photovoltaic sensing of a memristor based in LSMO/BTO/ITO ferroionic tunnel junctions

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American Institute of Physics
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Memristors based on oxide tunnel junctions are promising candidates for energy efficient neuromorphic computing. However, the low power sensing of the nonvolatile resistive state is an important challenge. We report the optically induced sensing of the resistive state of a memristor based on a La_0.7Sr_0.3MnO_3/BaTiO_3/In_2O_3:SnO_2 (90:10) heterostructure with a 3 nm thick BaTiO3 ferroelectric barrier. The nonvolatile memristive response originates from the modulation of an interfacial Schottky barrier at the La_0.7Sr_0.3MnO_3/BaTiO_3 interface, yielding robust intermediate memristive states. The Schottky barrier produces a photovoltaic response when illuminated with a 3.3 eV UV LED, which depends on the state. The open circuit voltage V_oc correlates linearly with the resistance of each state, enabling active sensing of the memristive state at light power densities as low as 20 mW/cm^2 and temperatures up to 100 K. This opens up avenues for the efficient and minimally invasive readout of the memory states in hybrid devices.
©2022 AIP PUblishing The transmittance characterization of the top ITO electrode was performed in collaboration with Dr. Riccardo Frisenda in the ICMM-CSIC. This work was supported by Spanish MCI through Grant Nos. MAT 2017-87134-C02 and PCI 2020-112093. G.S.-S. acknowledges financial support from Spanish MCI via Grants Nos. RTI2018-099054-J-I00 (MCI/AEI/FEDER, UE) and IJC2018-038164-I. Electron microscopy observations were carried out at the Centro Nacional de Microscopia Electronica, CNME-UCM. This material was based upon the work supported by the U.S. Air Force Office of Scientific Research under Award No. FA9550-20-1-0242.