Microstructure and electrical properties of LaMnO3-CaCu3Ti4O12 composite ceramics

In this study, x LaMnO 3 -(1 −  x )CaCu 3 Ti 4 O 12 (0 ≤  x  ≤ 0.7) composite ceramics have been prepared by the conventional solid-state method. XRD results show that the composite ceramics are mainly composed of LaMnO 3 and CaCu 3 Ti 4 O 12 phases. Electrical property analysis shows that the resistivity ρ 25 gradually decreases from 2.17 × 10 8 to 1.74 × 10 5 Ω·cm with increasing LaMnO 3 content. The relationship between ln ρ and 1000/ T is not linear and changes around 350 °C. In the temperature range of 0–350 °C, the activation energy E a 0–350 °C decreases gradually with the increase of the LaMnO 3 content. In the temperature range of 350–500 °C, the activation energy E a 350–500 °C increases first and then decreases, which is related to the variation of oxygen vacancy. The compounding of LaMnO 3 gives rise to the decrease in B value, thus, providing the potential for the applications of wide temperature range thermistors. After annealing, the coefficient of aging (Δ R / R ) of the composites decreases from 23.73 to 3.01%.