A-site-deficiency-dependent structural, magnetic and magnetoresistance properties in the Pr0.6Sr0.4MnO3 manganites

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 251 K for the strontium-deficient sample, 273 K for the stoichiometric sample and 275 K 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 0 T to 5 T. The strontium-vacancy sample has been proven to exhibit a magnetoresistance value of about 50% at 266 K at a magnetic applied field of 5 T and seems to be constant below 236 K. 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.