Electrical property of Al/La/Cu modified ZnO-based negative temperature coefficient (NTC) ceramics with high ageing stability

Negative temperature coefficient (NTC) ceramics based on simple ZnO were prepared and investigated in present work, where slight amount of Al- and La- ions were added as semiconductor dopants, and Cu-ions were selected as the sintering agent and property modificator. All the prepared ZnO-based ceramics have a wurtzite structure and show typical NTC characteristic. For various contents of Al-, La- and Cu- ions in ZnO-based ceramics, ρ25 can be adjusted from 0.65 kΩ cm to 3.28 MΩ cm, and B values were obtained in range of 2500 K to 5850 K. The ageing treatment at 125 °C for 600 h in air revealed that the ZnO-based ceramics have high thermal stability with the resistance shift < 2%. The complex impedance spectra were applied to analyze the electrical performance.