Investigando a influência da temperatura de sinterização na topografia em nanoescala 3D de filmes finos de manganita de Lântanio (LaMnO3)

Abstract

This work presents the detailed characterization of thin films of lanthanum manganite (LaMnO3), prepared by the sol-gel method. The research is of great relevance due to its potential for applications in electronic, optical and magnetic devices. Understanding their structural, thermal and morphological properties enables the development of more efficient and functional materials, contributing to significant advances in emerging technologies such as sensors, catalysts and energy storage devices. In this study, the substrate was dried and pre-sintered at 400ºC and then the samples were sintered between 650ºC and 850ºC. Thermogravimetric analysis (TG) and differential thermal analysis (DTA) determined the phase transition temperature of lanthanum manganite, which was observed to be higher than 650°C. FTIR analysis revealed the main functional groups, such as Mn - O - Mn vibrations, carboxylic groups and O - H bonds. XRD analysis showed spatial patterns depending on the sintering temperature of the films and showed that the samples sintered between 700°C and 800°C have an orthorhombic phase with Pbnm symmetry. The surface morphology of the thin films was analyzed using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) techniques. The images show the formation of homogeneous surfaces, without fractures and with an average grain size of around 200 and 300 nm. The average surface roughness ranges from 1.9 nm to 7 nm. The results obtained in this study highlight the importance of processing conditions, especially sintering temperatures, in the formation and properties of LaMnO3 thin films.