Open AccessA new method for investigating the conduction of ZnO-based varistor ceramics
Author(s) -
Shengtao Li,
Pengfei Cheng,
Yang Yan,
Le Zhang
Publication year - 2009
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.58.2543
Subject(s) - varistor , thermionic emission , materials science , quantum tunnelling , exponent , conductance , condensed matter physics , thermal conduction , ceramic , nonlinear system , atmospheric temperature range , schottky diode , thermodynamics , voltage , composite material , physics , optoelectronics , diode , electron , linguistics , philosophy , quantum mechanics
The IV characteristics of ZnOBi2O3, ZnOBi2O3MnO systems and commercial ZnO varistor ceramics were measured at temperatures in a wide range of -180?℃T<100?℃. It was found that experimental conductancetemperature curves under various currents can be theoretically reproduced by calculating conductance in parallel or series for mechanisms such as scattering mechanism, thermionic emission and tunneling effect. It was found that if the relation between a singlemechanism conductance and temperature obeys the exponential law with an exponent a little less than 1, then this mechanism will give rise to a high nonlinear exponent. The nonlinear exponent due to tunneling effect was 33, which was similar to the measured value of 43 for commercial ZnO varistor ceramics. This tunneling effect is active even at low electric field, especially in low temperature region.