Conduction mechanisms and 1/f noise in thick-film resistors with Pb3Rh7O15and Pb 2Ru2O7

Abstract
Thick‐film resistors with Pb3Rh7015 and Pb2Ru20 7 as conductors are considered. These compounds are chemically stable during the firing process of the resistors. The variation of sheet resistivity R with volume fraction conductor follows a simple power law. This result cannot be explained by percolation theory in its simple form. The conductivity is found to be independent of frequency up to 10 GHz. In both cases a small positive Hall coefficient is observed which is interpreted as being due to mixed electron and hole conduction. Finally the 1/ f noise is considered, and is found to vary approximately linearly with R. A theoretical model for the 1/f noise in thick‐film resistors is presented that accounts for this linear relationship. The observed deviations from linearity indicate that probably tunneling through barriers at the interfaces between the conducting grains is an important factor in determining the conduction.