Dependence of magnetic and structural properties of Ni0.5 M0.5 Fe2O4 (M=Co, Cu) nanoparticles synthesized by citrate precursor method on annealing temperature

Abstract

Ni_0.5M_0.5Fe₂O₄ (M = Co, Cu) ferrite nanoparticles were synthesized using citrate precursor method. The citrate precursor was annealed at temperatures 400^oC, 450^oC, 500^oC and 550^oC. The annealed powders were characterized using X-ray diffractometer (XRD) and vibrating sample magnetometer (VSM). Observed XRD data was further analyzed using Rietveld analysis which showed that particles annealed at temperatures upto 450^oC display cubic spinel structure while the particles formed at temperature higher than 450^oC display a tetragonal spinel structure. Sharp changes were observed in particle size, lattice constant, magnetization and retentivity in the range 450-500^oC temperature suggesting that nucleation/growth mechanism is different at temperatures above and below a critical temperature in this range.

Keywords: Ferrites, magnetic nanoparticles, citrate precursor, magnetization

International Journal of Engineering, Science and Technology, Vol. 2, No. 8, 2010, pp. 73-79