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Influence of thermal annealing treatment in oxygen atmosphere on grain boundary chemistry and non-ohmic properties of SnO2·MnO polycrystalline semiconductors

✍ Scribed by Orlandi, M. O. ;Bueno, P. R. ;Longo, E.


Book ID
105364495
Publisher
John Wiley and Sons
Year
2008
Tongue
English
Weight
434 KB
Volume
205
Category
Article
ISSN
0031-8965

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✦ Synopsis


Abstract

The present work studied the influence of thermal treatment in oxygen rich atmosphere on heterogeneous junctions in Mn‐doped SnO~2~ polycrystalline system presenting varistor behavior. The samples were prepared by conventional oxide mixture methodology, and were submitted to heat treatment in oxygen rich atmosphere at 900 °C for 2 h. The samples were characterized by X‐ray diffraction, scanning electron microscopy, dc and ac electrical measurements. The results showed that there is an evident relationship between the microstructure heterogeneity and non‐ohmic electrical properties. It was found that for this SnO~2~·MnO‐based varistor system the heat treatment in oxygen rich atmosphere does not necessarily increase the varistors' properties, which was related to the decrease in the grain boundary resistance. The results are compared with Co‐doped SnO~2~ varistors and ZnO based varistors. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)