Antibacterial activities of Bi-Ag co-doped cobalt ferrite and their ZnO/Ag nanocomposite/s

•Sol-gel method is widely used to synthesize co-doped cobalt ferrite.•ZnO/Ag nanocomposites of samples were prepared by mortar and pestle grinding method.•X-ray diffraction technique was used to study the crystal structure and size.•Compositional analysis was done using FTIR in most of the cases.•Antibacterial activities were studied using Agar disk diffusion test.