Toward Controlling Filament Size and Location for Resistive Switches via Nanoparticle Exsolution at Oxide Interfaces

Abstract

Memristive devices are among the most prominent candidates for future computer memory storage and neuromorphic computing. Though promising, the major hurdle for their industrial fabrication is their device-to-device and cycle-to-cycle variability. These occur due to the random nature of nanoionic conductive filaments, whose rupture and formation govern device operation. Changes in filament location, shape, and chemical composition cause cycle-to-cycle variability. This challenge is tackled by spatially confining conductive filaments with Ni nanoparticles. Ni nanoparticles are integrated on the bottom La 0.2 Sr 0.7 Ti 0.9 Ni 0.1 O 3−δ electrode by an exsolution method, in which, at high temperatures under reducing conditions, Ni cations migrate to the perovskite surface, generating metallic nanoparticles. This fabrication method offers fine control over particle size and density and ensures strong particle anchorage in the bottom electrode, preventing movement and agglomeration. In devices based on amorphous SrTiO 3 , it is demonstrated that as the exsolved Ni nanoparticle diameter increases up to ≈50 nm, the ratio between the ON and OFF resistance states increases from single units to 180 and the variability of the low resistance state reaches values below 5%. Exsolution is applied for the first time to engineer solid-solid interfaces extending its realm of application to electronic devices.

Boosting methane partial oxidation on ceria through exsolution of robust Ru nanoparticles

“…After the exsolution treatment (5%H 2 , 900 ºC, 2h) exRuCeO 2 material, the main peak shifted to 769 ºC. Interestingly, when increasing the exsolution treatment up to 5h (Fig.3c) the nanoparticles size increase, as previously observed in Ni exsolution in perovskites, 47,48 and grow solely in the edges of the oxide particles, which progressively change from a rounded-like shape into a 12 metal state, corroborating that the exsolved nanoparticles observed by SEM ( Fig.3) and TEM ( Fig.4) are solely composed by Ru metal. XPS analysis of Ce3d core-level spectra are depicted in Fig.…”

Exploring the Stability of Fe–Ni Alloy Nanoparticles Exsolved from Double-Layered Perovskites for Dry Reforming of Methane

“…For instance, in the work of Du et al, they obtained FeNi 3 exsolution from Sr 2 FeMo 0.65 Ni 0.35 O 6−δ after 10 h of treatment in pure H 2 [22]. Increased exposure times and higher H 2 concentrations, as performed by Du et al compared to our work, commonly resulted in larger particle sizes [34,35]. Formation of larger particles could eventually ease their detection by XRD, and, thus the identification of the actual alloy composition of the exsolved nanoparticles.…”

“…This characteristic anchoring, typical of nanoparticle exsolution, avoids sintering with neighboring particles due to the high degree of attachment of the nanoparticles to the oxide surface. Figure 4b-f shows the HAADF-STEM image and EDX mapping of An alternative way to tune the particle size in exsolution is with temperature [12,34,35,38]. In order to explore this aspect, we treated the double layer perovskite mate- An alternative way to tune the particle size in exsolution is with temperature [12,34,35,38].…”

“…Figure 4b-f shows the HAADF-STEM image and EDX mapping of An alternative way to tune the particle size in exsolution is with temperature [12,34,35,38]. In order to explore this aspect, we treated the double layer perovskite mate- An alternative way to tune the particle size in exsolution is with temperature [12,34,35,38]. In order to explore this aspect, we treated the double layer perovskite materials at 700 and 800 °C and compared them with the original exsolution temperature, 900 An alternative way to tune the particle size in exsolution is with temperature [12,34,35,38].…”

“…In order to explore this aspect, we treated the double layer perovskite mate- An alternative way to tune the particle size in exsolution is with temperature [12,34,35,38]. In order to explore this aspect, we treated the double layer perovskite materials at 700 and 800 °C and compared them with the original exsolution temperature, 900 An alternative way to tune the particle size in exsolution is with temperature [12,34,35,38]. In order to explore this aspect, we treated the double layer perovskite materials at 700 and 800 • C and compared them with the original exsolution temperature, 900 • C. As observed in Figure 6a, there were remarkable differences on the exsolved nanoparticle sizes when lowering the temperature.…”