Investigation of the effect of phase transformations on the magnetic and electrical properties of Co/Co3O4 nanowires

Abstract The paper presents the results of a study of changes in the phase composition, magnetic and electrical properties of Co nanowires during thermal annealing in the temperature range 200–600 °C. The electrochemical deposition method was used as a method for producing Co nanostructures; polymer films with a pore diameter of 400 nm and a thickness of 12 μm were used as templates. In the course of the study, the dependences of the change in structural characteristics and phase composition on the annealing temperature were established. Three stages of evolution of the structural characteristics and phase transformations of nanostructures consisting of thermal annealing of defects and ordering of the crystal structure at low temperatures, the formation of the oxide phase and its domination in the structure with the subsequent phase transition from Co-C/Co-H to Co3O4 are determined. It is established that the appearance of the oxide phase leads to a change in the magnetic properties and the formation of the structure characteristic of paramagnets. In the course of the study of the conductive characteristics, it was found that an increase in the annealing temperature first leads to annealing of defects and an increase in conductivity, however, at a temperature of 600 °C, a deterioration in the conductive properties is observed.