Nanocrystalline Co0.5Zn0.5Fe2O4 ferrite: Synthesis, characterization and study of their magnetic behavior at different temperatures

Abstract

Co0.5Zn0.5Fe2O4 ferrite nanocrystals with average diameter in the range of 5–6nm have been synthesized by reverse microemulsion technique. X-ray diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM) are used to characterize the structural, morphological, and magnetic properties. X-ray analysis showed that the nanocrystals possess cubic spinel structure. The absence of hysteresis, negligible remanence, and coercivity at 300K indicate the superparamagnetic character and single domain in the nanocrystalline Co0.5Zn0.5Fe2O4 ferrite materials. The nanocrystalline Co0.5Zn0.5Fe2O4 ferrite was annealed at 600°C. As a result of heat treatment, the average particle size increases from 5nm to 7nm and the corresponding magnetization value increases to 15.94emu/g at 300K. However, at a low temperature of 100K, the annealed samples show hysteresis loop which is the characteristic of a superparamagnetic to ferromagnetic transition. A comparative study of the magnetic properties of Co0.5Zn0.5Fe2O4 ferrite nanocrystals obtained from (1) reverse microemulsion and (2) chemical co-precipitation route has also been carried out.