Crystalline Structure, Surface Morphology of Perovskite Manganites Nd_0.75Na_0.25Mn_1-yFe_yO₃

Abstract

The perovskite manganite oxide Nd_0.75Na_0.25Mn_1-yFe_yO₃ with y = 0, 0.10 and 0.15 samples have been systematically investigated to elucidate the effect of Fe-doped on the crystalline structure and surface morphology. However, study on reporting the relationship between crystalline structure and surface morphology for perovskite manganites is still limited. All samples were prepared using solid-state reaction method and characterized by X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM) with Energy Dispersive X-ray analysis (EDX) to determine the crystal structure and surface morphology as well as identifying the elemental composition. All samples have been observed as an orthorhombic structure with Pnma space group and the lattice parameter as well as the unit cell volume had changed due to the Fe do**. The values of unit cell volume were increase consistently from 227.0 ų (y = 0) to 228.1 ų (y = 0.15) which can be suggest that due to the size mismatch between the Fe³⁺ ions and Mn³⁺ ions. The morphological study depicts that the samples have compact and connected grain with well-defined grain boundary and there is not noticeable size change have been shown for all samples. However, the grain size shows an unsystematic trend when the concentration of Fe increase. Apart from that, the EDX measurement shows that all samples have an accurate composition without detected any impurities peak.