xLaCoO₃-(1-x)CaCu₃Ti₄O12 (0.02 x 0.15): a NTC thermosensitive ceramic with controllable electrical properties

In this study, a series of perovskite-phase xLaCoO(3)-(1 - x)CaCu3Ti4O12 [xLC-(1 - x) CCTO, with x = 0.02, 0.04, 0.08, 0.15] negative temperature coefficient (NTC) ceramics were fabricated by a solid-state reaction method. XRD analysis indicated that the ceramics consisted of a body-centered cubic perovskite phase. The grain size of the prepared samples was greatly decreased by introducing LC. The decrease in resistivity of all samples as a function of temperature indicated the presence of NTC effect in all the fabricated xLC-(1 - x)CCTO ceramics. The electrical resistivity rho(30) decreased within a relatively narrow range of 1.58 x 10(6) - 9.28 x 10(5) Omega cm with increasing LC content, whereas thermistor constant B-30/75 increased within a wide range of 2190-5232 K. Our outcomes confirmed that the combination of rho(30) and B-30/75 could be adjusted to desired values by incorporating LC. In addition, in situ XPS and complex impedance analysis displayed a conduction mechanism based on electron hopping. Current research provided a feasible example to achieve the suitable coupling of high rho and low B values for NTC thermistors.