Structural magnetic and Mossbauer study of ⁵⁷Fe doped La_2/3Ca_1/3Mn_1-xFe_xO₃ (0≥x≥0.1) manganites

We have studied the effect of ⁵⁷Fe substitution on structural and magnetic properties of La_2/3Ca_1/3Mn_1-xFe_xO₃ (LCMFO; x=0, 5 and 10%) manganites. The powders were prepared by the solid state reaction method, and the final products were characterized by X-Ray Diffraction (XRD), Mössbauer Spectrometry and Magnetic Measurements. Only one single phase corresponding to the manganite phase was detected without the presence of impurities or iron phases. The hyperfine parameters of Mossbauer spectra (MS), taken at different temperatures for the doped samples, reveal the only presence of Fe³⁺ ions in octahedral coordination. At low temperatures, the MS spectra were fitted with a model of three components associated to three magnetic phases of iron (ferromagnetic and paramagnetic states). These ordered and not ordered magnetic phases are related to the effects of grain size distribution in LCMFO samples. Finally, significant changes were observed in the saturation magnetization, Curie temperature and coercivity field with increasing of iron doping level.