Copper-substituted cobalt ferrite nanoparticles: Structural, optical and antibacterial properties

Economic and simple co-precipitation technique was used to synthesize cobalt ferrite nanoparticles (CuxCo(1-x)Fe2O4) where x = 0.0, 0.3, 0.5, 0.7 and 1.0. We systematically studied the crystal structure and antibacterial properties of samples as a function of Cu-substituted content. Increasing Cu concentration causes decrease in the nanoparticle size from ~30 to ~20 nm. Specific saturation magnetization (Ms), remanent magnetization (Mr) and coercivity (Hc) of the spinel ferrites are diminished by the substitutions of Cu+2 ions. FTIR spectra exhibit two prominent fundamental absorption bands at ~595 cm-1 and 419 cm-1. These bands correspond to intrinsic stretching vibrations of metal at tetrahedral and octahedral site respectively. The Raman scattering results reveal that increase in the Cu content enhances the local disorder at both tetrahedral and octahedral sub lattices. Moreover, we found that substitution of cobalt with copper leads to high reactive oxygen species (ROS) which in turn enhance the antibacterial ability, as exhibited by optical density and inhibition zone diameter (IZD). The results indicate that the substitution of Co with Cu in Co ferrite nanoparticles strongly influences the microstructure, crystal structure and particle diameter.