Study of magnetization and transport properties in La0.7Pb0.3MnO3 with the addition of nonmagnetic Ag Original Research Article

Magnetization and transport properties of Ag containing La0.7Pb0.3MnO3+x wt% Ag (x=0–20) system have been reported. The samples with high Ag content (x>10), Ag phase is observed along with the perovskite structure. Presence of non-magnetic Ag in La0.7Pb0.3MnO3 decreases the d.c magnetization along with increase of ferromagnetic Curie temperature. All the samples show metal-insulator transition (MIT) with peaks at the MIT temperatures depending on Ag content). Resistivity (ρ) decreases and Tp increase with increase of Ag content. For higher concentration of Ag (>10 wt%) decrease of ρ is small and Tp remains almost constant. Magnetoresistance ratio [MRR=−(ρ1.5T−ρ0T)/ρ0T)] also decreases with increasing Ag concentration. In the semiconducting regime (above Tp), resistivity data can be well fitted with small polaron hopping (SPH) model. Activation energy calculated from the SPH model decreases with Ag content. In the low temperature phase (T