A self-compliant selector-free memory with functional bismuth ferrite

Abstract

In-memory computing requires selector-free operation, low variability, and stable multilevel switching, all of which remain challenging to achieve in a single system. Here, we demonstrate a robust selector-free memory based on a multiferroic BiFeO3 that combines self-compliance with stable bipolar switching, high yield, long endurance, and extended retention. We observe that BiFeO3 memristive crossbar arrays become self-compliant through a naturally formed TiOx interfacial layer, enabling forming-free bipolar switching without external selector devices, addressing major bottlenecks that have limited the practical deployment of resistive memories. The array delivers stable bipolar switching with a 97% device yield, endurance beyond 105 cycles, and data retention exceeding 105 s with low cycle-to-cycle and device-to-device variability. In addition, the devices exhibit 16 well-separated conductance states, enabling 4-bit multilevel operation via precise pulse-controlled programming for digit visualization in edge applications. Noise measurements reveal predominantly 1/f-type behavior with minimal random telegraph noise, indicating robust conductance stability across the programmable window. These results establish BiFeO3 as a practical materials platform for multibit, selector-free crossbar memories offering high reliability, making it well-suited for scalable computing architectures based on functional materials.