Analog memory characteristics in epitaxial SrCoO_2.5 films of various thicknesses on (001)-oriented Nb:SrTiO₃ substrates

Memristors that exhibit stable switching behavior and analog memory characteristics are essential in neuromorphic devices, and strontium cobaltite thin films have been reported as a promising memristive materials. Most studies have focused on switching layers thicker than 25 nm, due to concerns regarding device instability and electrical breakdown in thinner films. However, reducing film thickness is desirable for lowering the operating voltage, enabling device integration, and improving energy efficiency. It is therefore essential to examine whether memristive operation can be maintained when the film thickness is reduced, and how the switching characteristics change in this regime. In this study, we investigate the memristive properties of brownmillerite SrCoO_2.5 epitaxial thin films with film thicknesses ranging from 5 to 25 nm. Electrical transport measurements were performed to investigate how film thickness and switching voltage range influence resistive switching behavior with attention to operating conditions relevant for neuromorphic applications.