Microstructure and Nonlinear Properties of Microwave-Sintered ZnO-V2O5 Varistors: II, Effect of Mn3O4 Doping

The microstructure and nonlinear current‐voltage characteristics of Mn3O4‐doped ZnO‐V2O5 ceramics, microwave‐sintered at 800°‐1200°C for 10 min, have been investigated. A high density (96% of the theoretical density) has been achieved. The incorporation of Mn3O4 additives does not significantly alte...

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Bibliographic Details
Published in:Journal of the American Ceramic Society 1998-11, Vol.81 (11), p.2949-2956
Main Authors: Kuo, Cheng-Tzu, Chen, Chang-Shun, Lin, I-Nan
Format: Article
Language:English
Subjects:
Applied sciences
Building materials. Ceramics. Glasses
Ceramic industries
Chemical industry and chemicals
Condensed matter: electronic structure, electrical, magnetic, and optical properties
Conductivity phenomena in semiconductors and insulators
Electronic transport in condensed matter
Electrotechnical and electronic ceramics
Exact sciences and technology
High-field and nonlinear effects
Physics
Technical ceramics
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Summary:The microstructure and nonlinear current‐voltage characteristics of Mn3O4‐doped ZnO‐V2O5 ceramics, microwave‐sintered at 800°‐1200°C for 10 min, have been investigated. A high density (96% of the theoretical density) has been achieved. The incorporation of Mn3O4 additives does not significantly alter the densification behavior of the ZnO‐V2O5 materials, but rather pronouncedly increases the nonlinear coefficient (α= 23.5) and markedly suppresses their leakage current density (JL= 2.4 10‐6 A/cm2). On the other hand, the intrinsic properties of the materials, including the Schottky barrier height (Phib) and the donor density (Nd), are only moderately modified; that is, Phib= 1.16 eV and Nd= 5.4 1017/cm3. X‐ray diffractometry analyses and energy‐dispersive X‐ray microanalyses (via scanning electron microscopy) indicate that the V2O5 species facilitate the densification and the development of microstructure via the formation of a liquid phase (Zn3(VO4)2) along the grain boundaries, whereas the Mn3O4 species markedly enhance the nonohmic behavior of the ZnO‐V2O5 materials by forming the surface states along the grain boundaries.
ISSN:0002-7820
1551-2916
DOI:10.1111/j.1151-2916.1998.tb02718.x