Study of electrical and magnetic properties of Pr_0.6−xBi_xSr_0.4MnO₃ (x=0.20 and 0.25)

We have investigated the electrical and magnetic properties of Pr_0.6-xBi_xSr_0.4MnO₃ (x=0.20 and 0.25) manganites. XRD data shows that the synthesized samples are single-phase and crystallize in the orthorhombic structure with Pnma space group. Resistivity measurements show that the sample with x=0.25 exhibits a thermally activated behavior for the entire temperature range. The magnetoresistance (MR) for the x=0.25 sample is as high as nearly 100% over a wide range of temperature, demonstrating its important technological application as a material for MR-based devices. From the magnetization measurements, two magnetic transitions viz. paramagnetic insulating to ferromagnetic metallic (PMI-FMM) transition at T_C and the ferromagnetic metallic (FMM) to antiferromagnetic insulating (AFI) transition at Neel temperature T_N were observe in both samples. The Curie temperature decreases with bismuth doping, while T_N increases with Bi content. Most interestingly, the temperature variation of magnetization and resistivity shows hysteresis behavior across the transition for the x=0.20 sample.