Synaptic memristors based on BaTiO3 thin films irradiated by swift heavy ions for neuromorphic computing

Abstract

Swift heavy ion (SHI) irradiation is an effective method for modulating the properties of thin oxide films by introducing defects, strains, and structural transformations. Here, we applied 516 MeV Xe³¹⁺ irradiation to BaTiO₃ (BTO) thin films grown on Nb:SrTiO₃ substrates to induce the generation of tracks and nanohillocks. Memristors with BTO films irradiated at a fluence of 5 × 10¹⁰ ions cm⁻² displayed excellent retention and endurance characteristics. Moreover, the memristors exhibited highly stable synaptic plasticity functions such as excitatory/inhibitory post-synaptic currents (E/IPSC) and paired-pulse facilitation/depression (PPF/D). The memristors achieved a discrimination accuracy of 92.5% on given handwritten digit data by an artificial neural network with supervised learning. These results verify that the judicious application of SHI irradiation on thin oxide films is a viable strategy for exploring neuromorphic computation.