The temperature dependences of resistivity of spinel-nanocarbon-epoxy composites

In this study, we investigated the electrical resistivity and its temperature dependence over the range of 77–293 K in epoxy composites filled with nanosized ferrites (CoFe2O4, CuFe2O4, NiFe2O4) and supplemented with multiwalled carbon nanotubes (MWCNTs) or graphene nanoplatelets (GNPs). The results reveal distinct conduction mechanisms associated with the geometry of the nanocarbon filler. Composites with GNPs exhibit both contact and tunneling conduction, while MWCNTs-filled systems demonstrate tunneling-dominated electron transport across the entire temperature range. The results indicate that careful control of the filler ratio allows tuning of the activation energy and resistivity profile, offering significant potential for applications in temperature sensors, flexible electronics, and self-regulating heating systems.