Structure and electrical properties of novel Mn3O4–LaMnO3 composite ceramics with NTC effect

Novel Mn3O4 - LaMnO3 composite ceramics have been successfully designed by the Pechini sol-gel routine, ceramics were calcined at 1450 °C for 12 h in air, and the electrical properties of its negative temperature coefficient at room temperature (300K) were investigated. X-ray diffraction and SEM results indicate that all the samples consist of two phases, LaMnO3 and Mn3O4, and illustrate highly crystalline quality. The electrical transport measurements show that the temperature coefficient of resistance (TCR) vs. temperature of the composite presents a 'U' shape at wide-temperature-range(188–350K), which is beneficial for the performance of practical devices. Low resistivity ρ and TCR revealed for pure LaMnO3, While TCR and room temperature range were increased with the addition of Mn3O4 phase into LaMnO3. Enhanced electrical properties with moderate resistivity ρ make it a prominent and potential candidate to be utilized in portable, uncooled bolometer.