On-line version ISSN 1980-5373
ORLANDI, Marcelo O.; BUENO, Paulo Roberto; LEITE, Edson Roberto and LONGO, Elson. Nonohmic behavior of SnO2.MnO2-based ceramics. Mat. Res. [online]. 2003, vol.6, n.2, pp.279-283. ISSN 1980-5373. http://dx.doi.org/10.1590/S1516-14392003000200025.
The present paper describes the nonohmic behavior of the SnO2.MnO-based system and analyzes the influence of the sintering time and the Nb2O5 concentration on this system's electrical properties. A nonlinear coefficient of ~7 was obtained for a 0.2 mol%-doped Nb2O5 composition, which is comparable to other values reported in the literature for the ternary SnO2-based systems. A recent barrier formation model proposed in the literature to explain the nonlinear electrical behavior of SnO2-based systems is used to clarify the role of the MnO constituent in the formation of the barrier, taking into account the influence of segregated atoms, precipitated phase and oxygen species in the grain boundary region.
Keywords : SnO2; varistor; semiconductor.