The effect of solution temperature on crystallite size and magnetic properties of Zn substituted Co ferrite nanoparticles

In this work zinc substituted cobalt ferrite nanoparticles (Co0.5Zn0.5Fe2O4) have been synthesized by the coprecipitationmethod, using stable ferric, zinc and cobalt salts with sodium hydroxide, at different solution temperatures, from room temperature to 363 K. The cobalt-zinc ferrite crystalline phase, the particle size and the morphology of the resulting nanoparticles were studied by X-ray diffraction and transmission electron microscopy. The average crystallite size of each sample was calculated from the broadening of the most intense peak (311), using Scherrer's formula and the results show crystallite sizes increased from 6 to 8 nm by increasing the solution temperature from room temperature to 363 K respectively. Room temperature VSM measurements show that the prepared nanoparticles have superparamagnetic behavior and did not saturate at maximum field of 800 kA/m. The variation of AC-susceptibility of the samples with respect to temperature was measured and it was found that the blocking temperature increased from 198 to 270 K by increasing the solution temperature from room temperature to 363 K respectively. FTIR spectra of the samples have been analyzed in the frequency range 400-4000 cm(-1), which also confirms the results of XRD. (C) 2009 Elsevier B.V. All rights reserved.