Propriedades estruturais e microestruturais de manganitas dopadas com cobre

Abstract

STRUCTURAL AND MICROSTRUCTURAL PROPERTIES OF Cu-DOPED MANGANITES. We report a structural study on polycrystalline La0.86 Sr0.14Mn1-yCuyO3+δ samples (y = 0, 0.05, 0.10, 0.15, 0.20) using refinement of powder X-ray diffraction data and analysis of scanning electron microscopy images. It is found that the structure remains rhombohedral through the whole series, with a decrease in the average Mn-Mn bond distances, slight variations in Mn-O-Mn angle and reduction in the unit cell volume with increasing Cu amounts. The values of Mn-Mn distances suggest compact structures with δ within ±1%. Scanning electron microscopy images reveal homogeneous microstructure in all samples, besides a trend for smaller grains and larger porosity with increasing Cu content.