Valence-induced distortion controls the resistivity and thermal stability of Co2.77Mn1.71Fe1.10Zn0.42O8 ceramics

Abstract

Spinel-type Co2.77Mn1.71Fe1.10Zn0.42O8 ceramics were first synthesized by modulating the different valence of manganese as raw materials. The results reveal that the valence effect of raw materials plays an essential role in the evolution of structural and electrical parameters, especially in the resistivity and aging coefficient. XPS quantitative analysis and Raman drift further prove that the Jahn-Teller distortion induced by Mn3+ cations changes the resistivity and thermal stability. Importantly, a novel double-hopping conduction model was proposed to elucidate the development of electrical properties. It indicates that the valence-induced distortion controls the resistivity and thermal stability of Co2.77Mn1.71Fe1.10Zn0.42O8 ceramics. The research of the relationship between material properties and the valence of the raw materials can be helpful to guide the production and experiment process. The novel conductive model will open a window for the conductive mechanism of spinel ceramics.

Keywords

• NTC ceramics
• Thermistors
• Microstructure
• Electrical properties
• Aging