Correlation between magnetic and electrical properties of the superparamagnetic La0.6Ca0.4MnO3 compound

Abstract

In this research work, we investigated the correlation between the electrical and magnetic properties of the superparamagnetic compound La_0.6Ca_0.4MnO₃ $\left(S0C1\right)$ prepared by the citric-gel method. The confrontation of the experimental data with the theoretical models revealed that the conduction at low temperatures, in the ferromagnetic metallic $\left(FMM\right)$ phase, can be mainly described by electron–electron $(e-e)$ and electron-magnon $(e-m)$ interactions. The contribution of the $(e-m)$ interaction, became weak for strong magnetic fields. At high temperatures, in the paramagnetic semiconductor $\left(PMSC\right)$ phase, the thermally activated hopping $\left(TAH\right)$ model proved to be the most appropriate to fit the experimental data. To describe the resistivity behavior in a wide temperature range including the phase transition region between the $\left(FMM\right)$ and $\left(PMSC\right)$ phases, we adopted the percolation model, based on the phase segregation mechanism.