The effect of cation distribution on magnetization of ZnFe2O4 nanoparticles

In this work zinc ferrite (ZnFe2O4) nanoparticles have been prepared by solgel method in two different media, one acidic and another one basic and then annealed at different temperatures from 350 to 800 degrees C. XRD investigations show that both samples have a single phase spinel structure. Mean crystallite sizes of the samples were calculated, using Scherrers formula, which are 13 and 16 nm for the samples prepared in acidic and basic media, respectively. The variation of cation distribution in the samples was estimated by the ratio of (2 2 0) and (2 2 2) intensity diffraction peaks and the results show that as-prepared nanoparticles have different ionic distributions in comparison with that of bulk zinc ferrite. Also the results show that by increasing annealing temperature the ionic distribution of the zinc ferrite nanoparticles tends to that of bulk sample. The magnetic properties of the samples were studied by VSM and the results show that zinc ferrite nanoparticles have a ferrimagnetic behavior. Also the morphology of the powders was examined by TEM. (C) 2010 Elsevier B.V. All rights reserved.