A model for quantitative description of magnetoresistance of the La$_{0.85}$Ba$_{0.15}$MnO$_3$ manganite below the curie temperature $T_c$ in the presence of colossal magnetoresistance effect near $T_c$

Precision resistive and magnetic measurements of the La$_{0.85}$Ba$_{0.15}$MnO$_3$ manganite with activation-type conductivity have been performed. Based on the experimental data, a mechanism has been proposed, which is sufficient for a quantitative description of the magnetoresistance below the Curie temperature $T_c$. The proposed mechanism predicts a considerable enhancement in the magnetoresistance near $T_c$ owing to an increase in the magnetic susceptibility. This implies that this mechanism can at least in part participate in the formation of colossal magnetoresistance. It has been concluded that all other mechanisms responsible for the effect of colossal magnetoresistance occur only near $T_c$. This restriction determines the specificity of the new approach to the problems of colossal magnetoresistance in lanthanum manganites.