Effect of Pr doping in La–Sn–Mn–O system

Abstract

We report the study on the effect of Pr doping on the structural and electrical properties of La0.9−xPrxSn0.1MnO3 (0 ≤ x ≤ 0.2) manganites. The X-ray diffraction (XRD) patterns for all the samples studied have been analyzed by Rietveld refinement method. The compounds are mixed phase with majority ABO3 (La1−xPrxMnO3) and minority La2Sn2O7 phases. The insulator–metal (I–M) transition temperature (TIM ∼ 237 K) of the pristine La0.9Sn0.1MnO3 sample shifts towards low temperatures and the resistivity increases with Pr doping. While the electrical conduction above TIM is dominated by the small polaron hopping, the metallic region below TIM is found to obey the electron–magnon scattering mechanism. With Pr doping, the conduction in metallic region shows a crossover from electron–magnon to electron–electron scattering. The re-entrant metal–insulator behaviour at low temperatures has been viewed in terms of the disordered metallic material and antiferromagnetic nature of PrMnO3. In conclusion the mixed multiphase system provided interesting structural and conduction mechanisms, being clubbed with each other.