x LaCoO 3 -(1 − x )CaCu 3 Ti 4 O 12 (0.02 ≤ x ≤ 0.15): a NTC thermosensitive ceramic with controllable electrical properties

In this study, a series of perovskite-phase x LaCoO 3 -(1 − x )CaCu 3 Ti 4 O 12 [ x LC-(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 x LC-(1 − x )CCTO ceramics. The electrical resistivity ρ 30 decreased within a relatively narrow range of 1.58 × 10 6 − 9.28 × 10 5 Ω 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 ρ 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 ρ and low B values for NTC thermistors.