Ba/Fe双掺LaCoO3热敏陶瓷材料低温离子传输机制研究

Research on the Low-Temperature Ion Transport Mechanism of Ba/Fe Co-doped LaCoO3 Thermosensitive Ceramic Materials

摘要:

为了开发电学性能优异的深低温材料，采用传统高温固态法制备了Ba/Fe双掺杂的LaCoO₃负温度系数热敏陶瓷材料，结合XRD、SEM、XPS等测试手段，研究了材料的物相结构、微观形貌、离子价态分布等，并在22—80 K和80—290 K范围内进行了低温电学性能测试。结果表明：双掺杂改性降低了LaCoO₃材料的应用温区，ρ（22 K）在1.85×10⁵—6.94×10⁶ Ω·cm范围内变化，材料常数B（22—100 K）在146.09—162.75 K范围内变化；在深低温环境下，材料的导电机理由80 K以上时的小极化子跳跃导电转变为80 K以下时的双交换导电，导致了材料常数B发生突变。由此证明，该双掺杂热敏陶瓷材料在极低温测试中具有可开发的应用潜力。

Abstract:

The development of deep and low-temperature materials with excellent electrical properties is of great significance to deep space exploration and other fields. In this study， Ba/Fe co-doped LaCoO₃ thermal sensitive ceramic material with negative temperature coefficient was prepared by traditional high temperature solid-state reaction method. The phase structure， microscopic morphology and ion valence distribution of the material were investigated by XRD， SEM， and XPS. The low-temperature electrical properties of LaCoO₃ were tested in the range of 22—80 K and 80—290 K. The results show that the temperature range of the LaCoO₃ material is reduced by co-doping modification. The ρ（22 K） is in the range of 1.85×10⁵—6.94×10⁶ Ω·cm， and the material constant B（22—100 K） is in the range of 146.09—162.75 K. In the deep and low-temperature environment， the conductive mechanism of the material changes from small polaron jump conduction above 80 K to double exchange conduction below 80 K， resulting in the abrupt change of the material constant B. The material system has potential application in the field of extreme low-temperature testing.