The diffusion study of oxygen atoms in Co x/3 Ni (5− x)/3 Sb 1/3Fe 1O 4 ferrite

• Published in: Journal of magnetism and magnetic materials Vol. 219; no. 1; pp. 73 - 77
• Main Authors: Hemeda, O.M., El-Saadawy, M., Barakat, M.M.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 2000
• Subjects: Cation distribution; Diffusion coefficient; Ferrites; Lattice parameters; X-ray analysis; Ferrites; Cation distribution; X-ray analysis; Diffusion coefficient; Lattice parameters
• ISSN: 0304-8853
• DOI: 10.1016/S0304-8853(00)00345-0

The oxygen diffusion in polycrystalline samples Co x/3 Ni (5− x)/3 Sb 1/3Fe 1O 4 ( x=0, 1, 2, 3, 4) at an annealing temperature of 823 K for 1 min, was studied. The diffusion coefficient was calculated using the equation D=( σKT/ Ne 2) t. It was found that the oxygen diffusion is characterized by a relatively small activation energy (0.54 eV) and low pre-exponential factors D 0≈10 −13 –10 −14 cm 2 s −1 . These results suggest the oxygen diffusion in ferrite under consideration occurs by means of structural vacancies with their concentration about 10 −11–10 −13. The substitution of Co 2+ ions decreases the diffusion coefficient up to x=1 and then increase it. The X-ray analysis showed that the spinel phase was completely formed at 12 h sintered at 1473 K. From the correlation between ionic radius and radius of octahedral and tetrahedral sites, the theoretical lattice parameters were calculated and a suggestion of cation distribution for the given ferrites was determined.