Abstract
•Rietveld refinement show that the vacancies in the A-site has not effect on the structural of the studied samples.•The synthesized samples exhibit a paramagnetic–ferromagnetic transition at Tc.•The two deficient samples exhibit a semiconducting–metallic transition.•Different behaviors of MR are found: extrinsic MR for Sr deficient sample and intrinsic MR for Pr deficient one.
Structural, magnetic and magneto-transport properties of Pr0.6Sr0.4MnO3, Pr0.6Sr0.3□0.1MnO3 and Pr0.5□0.1Sr0.4MnO3 perovskite manganite oxides have been investigated. X-ray diffraction (XRD) analysis using Rietveld refinement has shown that all the samples under investigation crystallize in the orthorhombic structure with Pbnm space group. Strontium vacancy leads to an increase in the unit cell volume. Paramagnetic (PM) to ferromagnetic (FM) transitions have been observed in all the synthesized samples. The Curie temperature was found to be 251K for the strontium-deficient sample, 273K for the stoichiometric sample and 275K for the praseodymium-deficient one. With the decrease in temperature, the two deficient samples exhibit semiconducting–metallic transitions. The resistivity decreases while Tρ increases with the change in the magnetic applied field from 0T to 5T. The strontium-vacancy sample has been proven to exhibit a magnetoresistance value of about 50% at 266K at a magnetic applied field of 5T and seems to be constant below 236K. The praseodymium-deficient one is manifested in another form of MR which increases with the decrease in temperature. This is a clear indication of the low field magnétoresistance (LFMR) behavior.