INFLUENCE OF La3+ WITH Pr3+ TO STRUCTURE, MICROSTRUCTURE, AND MAGNETOTRANSPORT PROPERTIES IN BARIUM MANGANITE PEROVSKITE

Abstract

Polycrystalline perovskite manganite of (La,Pr)_0.67Ba_0.33MnO₃ bulk ceramic samples were synthesized by conventional solid-state route. The structure, microstructure, electrical and magnetic properties were studied. Substitution of La³⁺ with Pr³⁺ promote coarsening of microstructure formation and influencing the connectivity of grains which resulting an increase in resistance. This substitution promotes magnetic dilution and consequently leading to the suppression of magnetic behaviour. The metal-insulator transition temperature, TP drops drastically from 264K (LBMO) to 127K (PBMO). PBMO displayed higher %MR in 10kG applied external magnetic field at room temperature which is -8.8% as compared to LBMO (-5.2%) because of magnetic dilution and reduced the magnetic saturation. Meanwhile, reduction in bond angle and bond length of Mn^3+-O^2--Mn⁴+ due to the distortion in MnO₆ might enhance DE and JT mechanism. In this work, the %MR at room temperature enhanced by replacing La³⁺ with Pr³⁺ but weaken the LFMR effect.