The effect of substrate-induced defects on structural and resistive switching properties in Gd0.2Ca0.8MnO3 thin films

Abstract

Gd0.2Ca0.8MnO3 thin films were deposited on various substrate materials and their structural and resistive switching (RS) properties were investigated. The deposition resulted in epitaxial and polycrystalline films, with the latter also exhibiting distorted film surfaces. Both epitaxial and a part of polycrystalline films used as RS devices showed consistent RS performance in which an order of magnitude, or higher, switching ratios were achieved between high and low resistance states. The devices showed strong endurance during repeated switching cycles. However, under retention characterization, the resistance states did not remain distinguishable in devices constructed on polycrystalline films, while other devices maintained separable resistance states. The RS results are discussed in relation to the structural characteristics of the films, and this work helps us understand the RS mechanisms that still remain elusive in manganite-based devices.

Importance of growth method and substrate-induced crystalline quality in Al/Gd0.2Ca0.8MnO3/Au memristor devices

“…Our previous research has already shown the existence of RS characteristics in GCMO, prepared both by PLD and CSD, on single crystal STO substrates [23,30,40]. The phenomena are again confirmed here in addition to the Si/STO substrate as well for both deposition methods as depicted in figure 4(a) for PLD and (c) for CSD-prepared films on STO.…”

“…It is noted that due to apparent instability in PLD Si/STO the bipolar nature of the RS becomes indistinct. However, in our previously published research the bipolar RS is apparent in an identical device [40]. Similarly, to what was observed in PLD, CSD STO (c) demonstrates improved performance over CSD Si/STO (d), indicating that the STO buffer layer incorporated in the silicon substrate significantly reduces RS characteristics, which corresponds to a decrease in the film crystal quality.…”

“…The phenomenon of RS in manganite-based systems is seen to be linked to interfacial oxygen exchange between two acting electrodes [48][49][50][51][52][53]. Our previous research demonstrates that epitaxial films are not a prerequisite for the RS phenomenon in GCMO [40]. This is also suggested by the work conducted on various manganite-based devices reported in the literature [54][55][56][57][58].…”