Nd1-xSrxMnO3 (x = 0.3): A perovskite manganite ceramic that exhibits PTC and NTC double properties

Nd1-xSrxMnO3 (NSMO, x = 0.280, 0.300, 0.330, 0.350, and 0.375) polycrystalline ceramics were fabricated using the sol-gel method. The crystal structure, surface morphology, valence state, elements distribution, and electrical properties were examined to understand the effect of Sr doping on NdMnO3 ceramics. The resistivity of the NSMO ceramics was measured using a standard four-probe method. The results obtained revealed that Sr doping significantly decreased the resistivity of the ceramics, which can be explained by the double exchange (DE) interaction and small-polaron hopping (SPH) model. The Nd0.70Sr0.30MnO3 ceramic had a positive temperature coefficient (PTC) of resistivity (16.69% K−1) at 197.5 K, and is expected to be used for preparing electronic switches with high sensitivity. Additionally, the NSMO ceramics maintained a stable negative temperature coefficient (NTC) of resistivity (−1% K−1) for x = 0.300 in the temperature range of 210.6–342.5 K. In conclusion, it is worth exploring materials with a high PTC and NTC over an extended temperature range, possessing the double potential function for high sensitivity or wide-temperature detection for electronic switches or infrared bolometers.