Influence of synthesis methods on the structural, dielectric and magnetic properties of cobalt ferrites

Abstract

A systematic study comprising structural, magnetic and dielectric properties of the cobalt ferrite (CoFe2O4) powders at first is carried out by way of synthesizing the materials using different preparatory methods, such as conventional solid-state method, wet chemical sol-gel autocombustion method using citric acid as well as glycine, separately as fuels. X-ray diffraction (XRD) studies reveal the formation of spinel phase with clear variations of peak intensities in all the samples. Morphology studies using scanning electron microscopy (SEM) reveal well grown grains in solid state synthesized sample compared to sol-gel autocombustion samples. The variations observed in the grain growth as well as densities (porosity) were attributed to typical temperature treatment conducted on the samples. Dielectric tests provide the evidence of space charge polarization in all the samples. Magnetic studies using vibrating sample magnetometry (VSM) provide the values of saturation magnetization and coercivity of the samples explored. The sol-gel autocombustion sample using glycine matrix (Cogly) shows higher saturation magnetization (Ms = 59.2 emu/gm) comparing to other samples whereas, sample with citric acid matrix results with lower Ms value as 36.5 emu/gm. The typical reasons for the observed variations in structural, microstructural, magnetic, dielectric and impedance properties of these materials were well addressed in terms of theoretical aspects and presented in this paper.