Zr ⁴⁺ ‐Tailored TiO ₂ Memristors With Highly Linear Synaptic Plasticity for Neuromorphic Learning and Low‐Power Memory Technologies

ABSTRACT This study reports the design and neuromorphic functionalization of solution‐processed Al/TO/FTO and Al/ZTO/FTO memristive devices, engineered through Zr ^{4 +} aliovalent doping to modulate defect chemistry within TiO ₂ . Structural, morphological, and spectroscopic analyses (XRD, FESEM, XPS) confirm successful incorporation of Zr ^{4 +} ions, leading to refined nano crystallinity, enhanced oxygen‐vacancy density, and a stabilized anatase framework. The Zr‐doped device exhibits analogue bipolar resistive switching with reduced operating voltages and conduction governed by Ohmic transport, space charge‐limited conduction, Poole–Frenkel emission, and direct tunnelling. Superior electrical stability is demonstrated through endurance exceeding 10 ⁴ cycles and retention beyond 10 ³ s. Importantly, the Al/ZTO/FTO device delivers highly linear and symmetric long‐term potentiation and depression, along with a paired‐pulse facilitation index approaching 98%, effectively emulating biological synaptic plasticity. Its neuromorphic capability is further validated using a convolutional neural network trained on the MNIST dataset, achieving a recognition accuracy of 98.28% over 50 epochs. These findings position Zr ^{4 +} ‐engineered TiO ₂ as a promising platform for scalable analogue memory, artificial synapses, and low‐power neuromorphic computing.