Combinatorial Screening for Europium Induced Defect Engineering in Titania Anodic Memristors

ABSTRACT A Ti‐Eu thin film combinatorial library with a composition ranging from 3 to 17 at.% Eu is fabricated by co‐sputtering and followed by anodic oxidation. Systematic screening of the electrical behaviour of the resulting anodic memristors revealed forming‐free, analogue switching behaviour, with higher Eu content alloys (7–17 at.% Eu) demonstrating enhanced endurance and multi‐level switching. The best performing alloy composition in terms of memristive behaviour is identified as Ti‐15 at.% Eu, with a high‐to‐low resistance ratio of 10 ⁵ and three levels of intermediate switching. Transmission electron microscopy analysis revealed the resistive switching as being interfacial, based on ion migration intermediated by intrinsically defined nanoscale crystallites. This is further confirmed by current conduction analysis, demonstrating that the conduction is governed by field‐assisted filling and depletion of trap states. The defect engineered, volatile and self‐rectifying anodic memristors show promise in neuromorphic computing for mimicking synaptic functions.