About the electrical resistivity of the La1-xAxMnO3 manganites in microwave range

A study of the electrical resistivity in microwave range for a class of perovskite manganites was performed in this paper. The work strategy was the structural simulation of the considered materials: La_1-xA_xMnO₃ (A = Ca, Sr, Ba or A = Li, Na, K and Rb), with 0 ¿ x ¿ 0.4, respectively 0 ¿ x ¿ 1. Materials are characterized by colossal magnetoresistance and consequently present one or two peaks in the electrical resistivity versus temperature plots. Peaks are shifting slightly with the applied magnetic field intensity and also with frequency after an high-pass filter law. The frequency dependence of the material resistivity above T_Curie illustrates the resistivity peaks and indicates the influence of the electromagnetic field variations on the electrical conduction mechanism inside the materials. The link between structure, field and properties was evidenced in this case, using the features and advantages of our simulation method.