Structural studies of nanosized nickel-substituted cobalt ferrite, synthesized by sol-gel method

In this study Ni substituted cobalt ferrite nanopowders Co1-xNixFe2O4 (x=0.1, 0.3, 0.5, 0.7 and 0.9) were prepared by sol-gel method. Phase identification of the samples was performed by X-ray diffraction (XRD) and mean crystallite sizes of 30 nm were calculated by Scherrerʾs formula. The results show that a minimum calcining temperature of 500 ºC is required to obtain a single phase spinel structure for all samples. It was observed that the lattice parameter of the samples decreases from 8.35 Å to 8.29 Å as Ni decreases. Magnetic measurements were carried out on cold pressed samples and the results show that as the value of x increases saturation magnetization decreases. Curie temperatures of the samples were measured and the results show that by increasing the x values the Curie temperatures of the samples increase. This increase was explained based on the change of superexchange interactions between different magnetic ions. Also the coercive forces of the samples were decreased by increasing x values which was explained based on the changes of anisotropy energy

کلیدواژه ها:

Sol-gel method ، Nanopowders ، Nickelcobalt ferrite ، magnetic properties ، superexchange interactions