Generally, strontium-doped lanthanum manganites (LSM) are materials connected ordinarily as cathodes in the solid oxide fuel cell (SOFC). In this study, the structural, optical, electrical and magnetic properties of LaSrMnO (x = 0.2, 0.5, 0.8) synthesized using an organic acid precursor strategy were investigated, based on using citric acid as a fuel. Evidently, the results disclosed that a pure single monoclinic LSM phase was obtained from the thermally treated precursors annealed at 1000 °C with an annealing time of 2 h. The microstructure of the formed sample relied on the Sr ion content. Moreover, a good optical transparency of 45-60% in a wide range of wavelengths between 800 and 1800 nm for all samples substituted by Sr ions was performed. The optical band gap energy was increased from 2.09 to 2.76 eV by increasing the Sr ion molar ratios. The trend in the calculated refractive index, the high frequency dielectric constant (ε) and the static dielectric constant (ε) of all the produced samples can be linked to an increase in the Sr ion concentration. Moreover, the magnetic properties were enhanced with increasing Sr ion content.

This study reported the doping of polyaniline (PANI) with graphene (G) and multi-walled carbon nanotubes (MWCNTs) by in situ polymerization. The molecular structure of PANI and its composites was observed by FTIR, which shows that the intensity of composites peaks are higher than pure PANI due to charge transfer between the PANI and graphitic allotropes. The structural information and crystallinity of PANI and its composites can be deduced from X-ray diffraction. The morphological characterization was observed by transmission electron microscope, which elucidated that aniline molecules were physically adsorbed and polymerized on the surface of graphene and MWCNTs due to p-p* electron interaction. PANI represents as an external layer of composites with several diameters depending on the PANI deposition degree, where the cores are G and MWCNTs. The conductivity measurement clarified the conductivity value of 0.1 wt% G in PANI matrix is higher 17 times than PANI without it.

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We report on the synthesis and characterization of lanthanum strontium manganite with tunable optical, magnetic and electrical properties.