Structure, microstructure, electrical transport mechanism and magnetoresistance in La_0.8Ag0_.2MnO₃

Abstract

Bulk polycrystalline sample of La0.8Ag0.2MnO3 has been successfully synthesized by the sol gel method. Structural, morphology, electrical properties and magnetoresistance has been investigated. Refinement results from XRD at room temperature showed a single-phase material with a rhombohedral crystal structure and R-3c space group. Electrical transport showed by comparison of experimental data with theoretical model, the sample undergo a metal-insulator transition at TM-I accompanying the ferromagnetic-paramagnetic transition. Data for temperature dependence of resistivity has been fitted using the formula ρ(T) = ρ FM f + (1 − f)ρ PM , ρ PM is resistivity of the ferromagnetic region, ρPM is resistivity of the paramagnetic region and f is the volume fraction of ferromagnetic phase. Result of fitted data is in good agreement with experimental data. MR measurements in the range of magnetic field 0-1 T, measurements were carried out at temperatures of 15 K, 100 K, 200 K and 285 K, the results showed a decrease in resistivity.