Mathematical and Computer Modeling as a Method for Studying the Hopping Conductivity of Manganites La0.5Ca0.5Mn1-xFexO3 (x = 0.6; 0.7; 0.8; 0.9)

Abstract

The article presents the results of applying a computer program created to identify the mechanisms of hopping conductivity in the doped materials to the study of the electronic properties of manganites La_0.5Ca_0.5Mn_1-xFexO₃ (x = 0.6; 0.7; 0.8; 0.9). Previously, the program code was tested on the materials La_0.5Ca_0.5Mn_0.5Fe_0.5O₃, La_0.7Ca_0.3Mn_0.5Fe_0.5O₃. The results of its work are in good agreement with the data obtained earlier. According to the results of the program, for the sample La_0.5Ca_0.5Mn_0.4Fe_0.6O₃ in a zero field the Mott variable range hopping conductivity (VRH) at temperatures of 170-300 K is observed. In the La_0.5Ca_0.5Mn_0.2Fe_0.8O₃ sample, the Shklovsky-Efros VRH is observed at 70-295 K and the Mott VRH in the range of 230-300 K. In a field of 1 Tl, the La_0.5Ca_0.5Mn_0.4Fe_0.6O₃ sample demonstrates the hopping conductivity over the nearest neighbors in both adiabatic and non–adiabatic regimes in the temperature range of 130-170 K, as well as the Shklovsky-Efros VRH at T=200-300 K. The program did not detect the hopping conductivity in the samples La_0.5Ca_0.5Mn_0.3Fe_0.7O₃ and La_0.5Ca_0.5Mn_0.1Fe_0.9O₃.