Conduction in RuO2-based thick films†

The dependence of RuO2-glass thick-film electrical conductivity on the concentration of metallic component reveals a metal-insulator transition. Resistance versus temperature characteristics measured in the range 4-2-400 K are presented for a set of seven composites of varying composition. The results obtained can be divided into two groups: composites incorporating ≥:0.12 (per unit volume) of metallic component yield minima of R( T) curves and possess parabola-like shapes, and composites with a small content of metallic component (<0.12) show a negative temperature coefficient of resistance over the whole range of measured temperatures. In the insulating region, data are analysed in terms of various conduction mechanisms, giving rise to an understanding of electrical conduction in RuO2-glass thick resistive films.