Structural Properties and Cation Distribution in Co^2+ and Ho^3+ Ions Induced Nanocrystalline ZnFe2O4

Nanocrystalline CoyZn1-yHozFe2-zO4 (where y = 0.0, 0.25, 0.5, 0.75, 1.00 and z=0.0, 0.03, 0.06, 0.08, 0.1) ferrites were prepared by sol-gel auto combustion method at pH of 8. Samples were obtained by annealing at relatively low temperature 600 C for 4 h and characterized by thermo gravimetric/differential thermal analysis (TG/DTA) all the samples were annealed at 600 C for 4 h. The prepared samples were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infrared (FT-IR) spectroscopy. Particle size measured from XRD and TEM are in good agreement with each other. The TEM study reveals the fine particle nature of the ferrites with little agglomerations. The cation distribution suggests that Zn2+ ion mainly on tetrahedral-A sites, Ho3+ ions shows strong preference towards octahedral-B site, Co2+ and Fe3+ ions are randomly distributed at the tetrahedral-A and octahedral-B site. FT-IR study confirmed two main absorption bonds in the frequency range 400-600 cm-1, assigned due to the tetrahedral-A and octahedral-B stretching vibrations.