Synthesis, characterization and influence of calcination temperature on magnetic properties of nanocrystalline spinel Co-ferrite prepared by polymeric precursor method

Magnetic particles of nanocrystalline cobalt ferrite has been synthesized successfully by polymeric precursor method and the influence of the calcination temperature on the particle sizes and magnetic properties of the synthesized samples have been also investigated. The particles have been calcined at different temperatures varying from 400 to 800 degrees C. The studies carried out using XRD, FT-IR, SEM, TEM, STA (TG-DTG-DTA) and VSM techniques. The results indicated that the ferrite samples obtained by this method had the nanocrystalline pure single-phase spinel structure and good magnetic properties. TEM images showed almost spherical nanoparticles which are uniform in both morphology and particle size distribution with sizes varied in the range of 13-145 nm with the calcination temperature. The gradual increase in the crystallite size with the calcination temperature indicates the formation of bigger particles on the calcination. Magnetic properties of the products were found greatly affected by the average crystalline size of the nanoparticles. The saturation magnetization and remanent magnetization values of the samples increased as a function of the calcination temperature. Our results showed this method facilitates the magnetic tunability of the Co-ferrite nanoparticles by using the proper temperature of the thermal treatment and greatly expanding the range of applications. (C) 2009 Elsevier B.V. All rights reserved.