Electrical, Magnetic, and Sensing Properties of Acetone in Co3–x Ni x O4‑rGO Samples

This study investigates the electrical, magnetic, and acetone detection properties of Co3–x Ni x O4-rGO (cobalt–nickel oxide reduced with graphene) samples synthesized using two different methods: sol–gel and hydrothermal. The structure, morphology, electrical, and magnetic characteristics of the samples are examined, highlighting a significant change in those with 4% Ni and rGO addition via the sol–gel method. It is determined that the samples exhibit varistor and thermistor behavior, with nonlinear coefficients and variable threshold voltages. The inclusion of rGO positively affects the electrical properties by improving charge carrier mobility. Additionally, the samples’ response to acetone as a target gas for vapor detection is investigated, observing significant changes in electrical resistance in its presence. Response times are short, with an acetone response R g/R of 2.5 at room temperature and 1.1 at 200 °C, with the latter being the same sample that exhibited changes in magnetic properties. This study provides a detailed insight into the electrical, magnetic, and acetone detection properties of Co3–x Ni x O4-rGO samples, highlighting the influence of the synthesis method on these properties and their potential for gas sensor applications.