Correlation between magnetic and electrical properties of La_0.7Ba_0.15Ag_0.15MnO₃ manganite prepared by sol gel method

We have reported the solgel synthesis, the structural analysis, and the correlation between magnetic and electrical properties of La_0.7Ba_0.15Ag_0.15MnO₃ manganite. The phase purity and structure of this sample were checked by X-ray diffraction technique and Rietveld analysis. M(T) measurement shows a ferromagnetic (FM)-to-paramagnetic (PM) phase transition of second-order type at Curie temperature T_C = 255 K. The obtained magnetocaloric parameters offer to the sample the possible use in the magnetic refrigeration technology. The resistivity data, ρ(μ₀H, T), show the presence of metal–semiconductor transition and a maximum magnetoresistance (MR) value of the order of 32% at magnetic field of 5 T. The phenomenological percolation model was used to study the conduction mechanism of the sample. It has been also shown that, from analyzing the temperature and magnetic field dependences of the electrical resistivity, it is possible to predict the behavior of the magnetization as well as the change of magnetic entropy near the phase transition temperature. The obtained agreement with experimental data for this analysis is quite reasonable.