Authors: A. Beitollahi, R. Sani, Yu.V. Maksimov and I.P. Suzdalev
Affilation: Iran University of Science and Technology (IUST), Iran, Islamic Republic of
Pages: 431 - 434
Keywords: nanopowder, cobalt ferrite, mechanical activation
In this work we report the phase formation and magnetic properties of CoFe2O4 nanopowder prepared by mechanical alloying technique using metallic cobalt and hematite powder (1:1 molar ratio) as the initial raw material in ambient air atmosphere. The formation of single phase cobalt ferrite of (Co2+ 0.18Fe3+ 0.82)[Co2+ 0.82 Fe3+ 1.18]O4 stoichiometry was confirmed for the samples milled above 15 hours without any heat-treatment by XRD and Mössbauer techniques. The average crystallite size of the sample milled for 30 h was ~ 13 nm. The highest room temperature value of the saturation magnetization (51 e.m.u./g) was obtained for the sample milled for 25h which was much lower than the corresponding value of the bulk cobalt ferrite due to the size effect.