The AC impedance and variable temperature dielectric spectroscopic analysis of MnO2 doped and un-doped ZnO–V2O5 ceramics

• Published in: Journal of materials science. Materials in electronics Vol. 23; no. 6; pp. 1143 - 1150
• Main Authors: Wu, Jun, Qi, Ting, Li, Taotao T., Qin, Qingwei W., Li, Guangqiang Q., Zhu, Bailin L., Xiang, Zhidong D., Xie, Changsheng S.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 2012; Springer
• Subjects: Applied sciences; Ceramics; Characterization and Evaluation of Materials; Chemistry and Materials Science; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Dielectric properties; Dielectric properties of solids and liquids; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Electronic equipment and fabrication. Passive components, printed wiring boards, connectics; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport in multilayers, nanoscale materials and structures; Electronics; Exact sciences and technology; Grain boundaries; Impedance; Materials Science; Optical and Electronic Materials; Physics; Surface double layers, schottky barriers, and work functions; Vanadium pentoxide; Zinc oxide; MnO2; Schottky Barrier Height; V2O5; Bi2O3; Nonlinear Coefficient; Performance evaluation; Grain boundaries; Varistors; Oxygen; Electrical conductivity; Vacancies; II-VI compound; Electrical properties; Schottky barriers; Depletion layer; Dielectric properties; Doping; Doped materials; Ceramics; Relaxation; Energy characteristic; Sintering; Vanadium oxide; Zinc oxide; Impedance; Grain boundary segregation; Activation energy; Electrical characteristic
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-011-0562-z

The electrical and dielectric properties of MnO 2 doped and un-doped ZnO–V 2 O 5 ceramics were studied by ac impedance and variable temperature dielectric spectroscopy. The results show that V and Mn ions simultaneously segregated at the grain boundaries to form an intergranular phase, increasing the resistivity of the intervening layer and the Schottky barrier at the grain boundaries, and then improving the varistor performance. An obvious loss peak appeared in all the samples, which means an effective depletion layer has formed. As for the samples sintered at 1,000 °C for 2 h, the activation energy of the characteristic relaxation process is about 0.339 eV for 99.5 mol% ZnO + 0.5 mol% V 2 O 5 and 0.352 eV for 99.0 mol% ZnO + 0.5 mol% V 2 O 5  + 0.5 mol% MnO 2 , respectively, which means this relaxation process is associated with oxygen vacancy .