Electrical and magnetic properties of La1−Sr MnO3 (0.1 ≤ x≤ 0.25) ceramics prepared by sol–gel technique

Abstract La1−xSrxMnO3 (0.1 ≤ x ≤ 0.25) high density ceramics were prepared by sol-gel method using methanol as solvent. X-ray diffraction analysis showed that all samples exhibited single perovskite structure and no second phase was detected. Scanning electron microscopy images exhibited good particle connectivity on the surface of sample, and grain size increased with the increase in Sr doping. Resistivity-temperature curves of samples were measured by standard four-probe method, and curves exhibited significant differences in studied range of Sr doping. Magnetic measurement results indicated that the variation of susceptibility of different samples was quite different, and the Curie temperature of samples increased with the increase in Sr content. For x = 0.2, temperature coefficient of resistance value of the sample was larger, and corresponding peak TCR temperature was 307.1 K, which is very close to room temperature. Thus, La0.8Sr0.2MnO3 ceramics exhibited high TCR value close to room temperature. Combined with its excellent magnetic properties, La0.8Sr0.2MnO3 ceramics may potentially act as effective candidates for uncooled radiation calorimeter and uncooled magnetic sensor. Applications of La0.8Sr0.2MnO3 ceramics in uncooled infrared radiation calorimeter at room temperature will be highly beneficial.