Structural Features of B-site Substituted Nano-Lanthanum Manganite

In this study, LaMn(1-x)FexO3 nanoparticles with x = 0, 0.5, and 1 were synthesized via citrate method [1]. Samples were studied by thermal gravimetric/ differential (TG/DTA) analysis, infrared spectroscopy, X-ray powder diffraction (XRD) and SEM characterizations. The structural characterization using commercial Xpert package and Fullprof program are witness for a structural phase transition in manganese replacement with iron. The structural analysis shows a rhombohedral toward cubic phase transition upon replacing of Mn by Fe in the form of LaMn(1-x)FexO3. The influence of Fe substitution on the crystal structure can be described by a tolerance factor [t=ra+rO/√2(rB+rO)] for estimation of deviation from the ideal structure. As a result, in Fe-substituted sample, t increases and rhombohedral structure transforms toward cubic structure, having higher symmetry [2]. Compared to the manganese, a more affinity is observed for the lanthanum toward iron for the cubic perovskite phase formation of LaBO3 (B: Mn or Fe) [3].