Structural, electrical and magnetic transport properties of Pr1_ xSrxMnO3 (0.30? x? 0.35) ceramics prepared by sol-gel method

In order to promote practical application of Pr1_xSrxMnO3 (PSMO, 0.30 <= x <= 0.35) ceramics in uncooled infrared bolometer, the effect of Sr content on the microstructure, surface morphologies, ionic valence, electrical and magnetic transport properties was investigated in detail. The crystal structure parameters such as, cell volume, Mn-O bond length increased as x rose, while the Mn-O-Mn bond angle decreased. In terms of electrical transport properties, more Sr content was beneficial to increase in Tp (metal-insulator (M-I) transition temperature) and Mn4+ ion concentration, the percentage of Mn4+ was increased from 18.71% to 23.33%. The Tp increased gradually as amount of Sr doping rose, which also led to the increase of peak temperature corresponding to temperature coefficient of resistivity (TCR). The reduction in resistivity was beneficial to improve TCR values. These phenomena could be explained by the double exchange (DE) interaction mechanism and the Jahn-Teller (JT) distortion effect. The increase in Tp is a result of enhanced DE interactions. The TCR peak temperature (Tk) of Pr0.65Sr0.35MnO3 ceramic was reached room temperature (5.77% K_ 1; 298.63 K), which is suitable for use in Pr-based uncooled infrared bolometers and is worthy of further investigation.