Investigating the Role of Reduced Graphene Oxide on the Structural and Transport Properties of LaMnO3

Abstract

The present work highlights the effect of reduced graphene oxide (rGO) on structural and charge transport properties of ( ${1} {-} {x}$ ) lanthanum manganite (LaMnO3). (x) rGO nanocomposites. The presence of dual phases within the nanocomposite specimens was well-established through comprehensive analysis employing characterization techniques, such as X-ray diffraction (XRD), Raman spectroscopy, and field-effect scanning electron microscopy (FESEM) etc. Furthermore, two distinct lattice spacings were identified by high-resolution transmission electron microscopy (HRTEM) measurements. Notably, the current versus voltage (I–V) profiles of the nanocomposites unveiled a distinctive bipolar resistive switching (RS) behavior. It was found that the increased concentration of rGO instigated an oxygen-deficient region, a phenomenon conclusively corroborated through X-ray photoelectron spectroscopy (XPS) analysis. Consequently, oxygen vacancies and ions alter the RS behavior of LaMnO3. Remarkably, the sample with ${x} =0.001$ exhibited superior RS characteristics when compared to ${x} =0.002$ and 0.005 samples. The conduction mechanism was found to be primarily governed by Ohmic and Schottky emission phenomena. The experimentally observed effect of rGO on RS property was also corroborated through first-principles-based calculations to offer a good degree of agreement. An increase in rGO concentration (x) reduces the bandgap, which brings about a semiconductor-to-metallic transition in the host material.