The present chapter summarizes the synthesis and characterization of Zinc Copper (ZnCu) ferrites due to their wide range of applications in many areas. ZnCu ferrites are soft magnetic materials that have exceptional electrical, magnetic, and optical properties. ZnCu ferrites possess high resistivity, permeability, permittivity, saturation magnetization and low power losses, and coercivity. The above features of ZnCu ferrites find application in designing transformers, transducers, and inductors. Ferrites are also used in magnetic fluids, sensors, and biosensors. Apart from these advantages, they play a vital role in practical appliances like mobile, laptops, mobile chargers, refrigerators, washing machines, microwave ovens, printers, and so on. Therefore, the present focus is on the literature of techniques of the synthesis, their characterization, the effect of doping on the behavior of ZnCu ferrite, and, finally, their potential application in technology.

Nanocrystalline SnO 2 and CuO doped with SnO 2 were prepared by the coprecipitation method and characterized for different physiochemical properties and microbiological activity. The composition and morphological formation were characterized by XRD, HRTEM, Raman, FTIR, and UV-vis spectroscopy. The Powder X-ray analysis reveals that Sn4+ ions have substituted the Cu 2+ ions without changing the monoclinic structure of SnO 2 but the average particle size of the SnO 2 and CuO doped SnO 2 samples from 11 and 5 nm respectively. However, it exhibits an inhibiting strong bacterial growth against tested bacterial strains.