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

摘要

Co0.5Zn0.5Fe2O4 ferrite nanocrystals with average diameter in the range of 5-6 nm 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 300 K 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 degrees C. As a result of heat treatment, the average particle size increases from 5 nm to 7 nm and the corresponding magnetization value increases to 15.94 emu/g at 300 K. However, at a low temperature of 100 K, 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. (C) 2015 Elsevier B.V. All rights reserved.