High-entropy (Co0.2Mn0.2Fe0.2Zn0.2Al0.2)3O4 thick-film NTC thermistor with high aging stability and wide temperature measurement range

Here, a novel type of high-entropy (Co0.2Mn0.2Fe0.2Zn0.2Al0.2)3O4 solid-solution ceramics with spinel phase structure was designed and successfully fabricated based on an entropy engineering approach. Additionally, the impact of sintering temperature, a critical factor in entropy stabilization, on structural and electrical behavior was systematically examined at a range of 1110∼1150 °C. The results indicate that each synthesized sample exhibits a single spinel structure in the F d¯ 3m (227) space group, and all five metal elements were uniformly distributed, demonstrating entropy stabilization. Meanwhile, the fabricated high-entropy ceramics manifest exceptional negative temperature coefficient (NTC) characteristics in the temperature range of 25 °C–350 °C. The aging stability is excellent as well. After aging at 150 °C for 1000 h, the ΔR/R0 of thick-film samples sintered at 1150 °C is less than 1 %. The successful synthesis of this novel class of spinel-type high-entropy ceramics introduces an emerging design approach for the development of NTC thermistors, particularly for applications in medium-temperature environments.