Effect of strontium deficiency on the transport and magnetic properties of Pr0.7Sr0.3MnO3

Abstract Ceramic samples of Pr 0.7 Sr 0.3− x □ x MnO 3 with x ⩽0.2 have been investigated by various techniques including 55 Mn nuclear magnetic resonance, SQUID magnetometry, resistivity and magnetoresistance measurements. On increasing x , the samples remain ferromagnetic at a low temperature with a decreasing Curie temperature, but a metal–insulator transition is observed. Besides, a positive magnetoresistance (MR) at very low temperatures with respect to a negative colossal MR at high temperatures is observed in the Pr 0.7 Sr 0.2 □ 0.1 MnO 3 sample.