Controlling temperature coefficient of resistivity in La1−xSrxMnO3 ceramics

We propose La1−xSrxMnO3 as a new lead-free and ruthenium-free conductive oxide used for thick film resistors. The temperature coefficient of resistivity (TCR) of the La1−xSrxMnO3 was controlled systematically by changing the composition x. The TCR behavior depended on the change of the crystal symmetries and the average valence of Mn ions. The highest value of 9356 ppm/°C was obtained at the x = 0.35. Zero TCR was realized around 0.200 < x < 0.225 and 0.45 < x < 0.50, where the critical x values were related to the characteristic change from Mott-insulator to metallic behavior. The systematical controlling TCR and the zero TCR are the first to be demonstrated for conductive oxide.