A-site-deficiency-dependent structural, magnetic and magnetoresistance properties in the Pr sub(0.6)Sr sub(0.4)MnO sub(3) manganites

Structural, magnetic and magneto-transport properties of Pr sub(0.6)Sr sub(0.4)MnO sub(3), Pr sub(0.6)Sr sub(0.3)[squ sub(0.1)MnO sub(3) and Pr sub(0.5)[squ sub(0.1)Sr sub(0.4)MnO sub(3) 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 I< for the praseodymium-deficient one. With the decrease in temperature, the two deficient samples exhibit semiconducting-metallic transitions. The resistivity decreases while T sub([)rho]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 Kata 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 magnetoresistance (LFMR) behavior.