Tuneable interfacial to filamentary resistive switching mechanism in room-temperature-grown amorphous YBa2Cu3Ox with excess Cu addition

Abstract

Resistive switching technologies have the potential not only to create large efficiency gains in computer memory but also to revo-lutionize emerging fields such as neuromorphic computing. In this paper, we report on novel resistive switching behaviour in devices made from room-temperature-grown Cu-rich amorphous YBa2Cu3Ox (YBCO) films, a material otherwise well-known as a high-temperature superconductor. In Nb:STO substrate / amorphous YBCO film (≈200 nm) / metallic Cu (15 nm) / metallic Pt (15 nm) devices, we demonstrate that the resistive switching can be tuned between mechanisms involving extended areas of the YBCO/electrode interface and a single-point filamentary mechanism simply by changing the Cu content of the deposition target and hence in the films. Changing the Cu content can also be used to optimise the properties of the devices further, with devices with an added 15 mol.% of Cu in YBCO initially providing an on/off ratio >100, switching endurance potential >6500 cycles, and state retention >2×10⁴ s, all at low switching fields of 0.3 MV/cm. The amalgam of promising resistive switching properties, fast growth (150 nm/min) at room temperature, and tuneability of the switching mechanism indicates the strong potential of this proof-of-concept amorphous system for future memory applications.