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

Novel Mn 3 O 4 - LaMnO 3 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, LaMnO 3 and Mn 3 O 4 , 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 LaMnO 3 , While TCR and room temperature range were increased with the addition of Mn 3 O 4 phase into LaMnO 3 . Enhanced electrical properties with moderate resistivity ρ make it a prominent and potential candidate to be utilized in portable, uncooled bolometer.