Mössbauer, magnetic and Optical studies of Mn substitution in Fe site of La0.67Ca0.2Ba0.13FeO3 nanomaterials

La _0.67Ca _0.20Ba _0.13Fe _1-xMn _xO ₃ (x = 0.0, 0.03 and 0.06) nanostructured perovskites synthesised by auto-combustion are studied in the present paper. They have a cubic structure with Pm-3 m space group. The crystallite and particle size, determined by transmission electron microscopy, decreases with increasing Mn content. Mössbauer spectroscopy revealed charge disproportionation of the type 2Fe ⁴⁺ → Fe ³⁺ + Fe ⁵⁺ , but not in accordance to the ideal reaction, perhaps due to the existence of oxygen deficiencies that increase with increasing Mn doping. Magnetic studies were performed and show that the magnetization decreases with increasing Mn substitution due to the reduction of grain size and the increase of AFM interactions associated to the Mn insertion. Fourier transform infrared (FTIR) spectra show that Mn doping does not significantly result in shifts of vibrational peaks.