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Critical behavior of the piezoresistive response in RuO2-glass composites

C. Grimaldi·T. Maeder·P. Ryser·S. Straessler
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Abstract

We re-analyse earlier measurements of resistance R and piezoresistance K in RuO2-based thick-film resistors. The percolating nature of transport in these systems is well accounted by values of the transport exponent t larger than its universal value t=2.0. Furthermore, we show that the RuO2 volume fraction dependence of the piezoresistance data fit well with a logarithmically divergence at the percolation thresold. We argue that the universality breakdown and divergent piezoresistive response could be understood in the framework of a tunneling-percolating model proposed a few years ago to apply in carbon-black--polymer composites. We propose a new tunneling-percolating theory based on the segregated microstructure common to many thick-film resistors, and show that this model can in principle describe the observed universality breakdown and the divergent piezoresistance.

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C. Grimaldi, T. Maeder, P. Ryser, S. Straessler. 2002-12-13. Critical behavior of the piezoresistive response in RuO2-glass composites. https://doi.org/10.1088/0022-3727%2F36%2F11%2F315

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