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Structural, Morphological, Raman, and Mossbauer Studies on (La0.8Ca0.2)(1-x)BixFeO3 (x=0.0, 0.1, and 0.2) Compounds
Authors: Issaoui, H ; Benali, A; Bejar, M; Dhahri, E; Santos, RF; Kus, N; Nogueira, BA ; Fausto, R; Costa, BFO
Ref.: J. Supercond. Nov. Magn. 32(6), 1571-1582 (2019)
Abstract: (La0.8Ca0.2)1−xBixFeO3 (x = 0.0, 0.1, and 0.2) compounds were prepared by the sol-gel method, using the citric acid route. Structural and microstructural characteristics of the samples were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy. Mossbauer spectroscopy was also used for magnetic characterization and structural confirmation of X-ray data. Refinement of XRD patterns indicated that the compounds crystallize in an orthorhombic structure, Pnma space group. The SEM measurements showed that the morphology of the samples is characterized by the existence of large agglomerates, while TEM confirmed the fine particle size. Raman spectra revealed that, when increasing temperature, the level of oxygen species adsorbed at the surface of the particles increases progressively. Room temperature Mossbauer spectroscopy data revealed the existence of two octahedral magnetic sites in the structure of the compounds, which is compatible with XRD data, and a small percentage of a paramagnetic phase in the samples, which increases with Bi-content.
