A conduction model for BaPbO/sub 3/-based thick film resistors

BaPbO/sub 3/-based thick film resistors were fabricated using BaPbO/sub 3/ powders and alkali glass frits. From microstructure observations, the conductive mechanisms are assumed to be related to the contact conditions between particles, and by means of EMT (effective-medium theory) approximation for some possible distributions, a more possible conductive model is proposed. This model is composed of trinary conductive channels, i.e., continuous, semi-continuous, and discontinuous, corresponding to a distribution function of the contact conductance, which is composed of trinary contact conditions, i.e., good contact, poor contact (both with same probability density) and no contact between BaPbO/sub 3/ particles. This model can explain the blending curve, temperature dependence and field dependence of resistivity of the specimens.<
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