Structural Transition in Thickness Dependent CSD Grown Nanostructure Manganite Thin Films

Abstract

In this report, manganite thin films of La0.7Sr0.3MnO3(LSMO) of various thicknesses are carried out by using Chemical Solution Deposition (CSD) technique on(100)– oriented single crystalline LaAlO3(LAO) substrate. Desired film thickness was achieved via control of the number of deposition sequences. X-ray diffraction (XRD) study shows that 1stand 3rdcoatings of LSMO films have the cubic structure while 5thand 7thcoatings of LSMO films have hexagonal structure. As the film thickness increases, increase in lattice parameter(c)was observed. Surface morphological study was carried out using Atomic Force Microscopy (AFM). RMS roughness and grain size were found to increase with the thickness. It is interesting and noticeable that the structural transition occurs from cubic to hexagonal are clearly observed through XRD and AFM results. In electrical resistivity measurement, show the resistivity of all the samples decreases as the film thickness or grain size increases, but the trend inverts for the film with 7 coatings and the maximum MR with the value of 21.35 %, in Hexagonal structure.