Characterisations of La-Sr-Mn-O (LSMO) Thin Film Fabricated by RF Sputtering

Abstract

A revisited study of perovskite-based manganite La0.67Sr0.33MnO3 (LSMO) deposited onto corning-glass (CG) substrates is reported here. The LSMO films were fabricated with RF sputtering with different deposition times, varying from 60 to 180 min, resulting in films with thicknesses of 35.0–109.7 nm. Rietveld refinements of the XRD spectrum showed that the samples exhibited hexagonal structures with a space group of R-3c (167) and remained unmodified structures. Clusters of monolayer growth were observed from the morphologies of the films. Interestingly, the average particle size obtained with an AFM perceived an insignificant variation of 31.7–35.6 nm despite the film thickness increment. Optical, electrical and magnetic properties were studied, as particle-size variation usually has a notable contribution to changes in these properties. It was found that the optical band gap (Eg) was in direct variation with the deposition time due to enhanced thickness and surface roughness. The temperature dependence of the resistivity graph was fitted with the percolation model to obtain further enlightenment on the electrical transport in the films. Low-field magnetoresistance (LFMR) was observed for all samples. Ferromagnetic to paramagnetic transition was observed in the vicinity of all samples’ TC values.