Interface-engineered Gd₂O₃/ZrO₂ bilayer memristor for emulating synaptic plasticity in neuromorphic systems.

Rare-earth-based materials are attracting growing interest for neuromorphic devices due to their unique electronic structures, defect engineering capabilities, and high ionic mobility, which enable energy-efficient and highly controllable memristive switching behavior essential for brain-inspired computing. In this work, we demonstrate a bilayer Ag/Gd₂O₃/ZrO₂/Pt memristor that exhibits robust resistive switching behavior and reliable synaptic functionality. The integration of a rare-earth Gd₂O₃ switching layer with a ZrO₂ modulation layer enables precise control over filament dynamics, resulting in a low operating voltage (<0.5 V), a high ON/OFF current ratio (∼108), stable direct-current (DC) endurance over 100 cycles, pulse endurance exceeding 5000 cycles, and long-term data retention beyond 5000 s. The device successfully emulates key biological synaptic functions, including short-term plasticity (paired-pulse facilitation and depression) and long-term potentiation/depression, with highly symmetric and linear conductance modulation. Furthermore, when the experimentally extracted conductance states are implemented in a multilayer perceptron network, a high pattern recognition accuracy of 97.5% is achieved on the MNIST dataset. These findings offer new insights into bilayer oxide architectures for scalable, energy-efficient, and hardware-level neurosynaptic systems.