Effects of Ga substitution on crystallographic and magnetic properties of co ferrites

Abstract

The crystallographic and magnetic properties of gallium-substituted cobalt ferrite (CoGaxFe2-xO4) were investigated. The new material was synthesized using conventional ceramic methods, with gallium substituted for ferrite in the range of x = 0.0 to 1.0, in steps of 0.2. X-ray diffraction and Mössbauer spectroscopy were used to confirm the presence of crystallized particles in the CoGaxFe2-xO4ferrite powders. All of the samples exhibited a single phase with a spinel structure, and the lattice parameters decreased as the gallium content increased. The particle size of the samples also decreased as gallium increased. For x ≤ 0.4, the Mössbauer spectra of CoGaxFe2-xO4could be fitted with two Zeeman sextets, which are the typical spinel ferrite spectra of Fe3+ with A- and B-sites. However, for x ≥ 0.6, the Mössbauer spectra could be fitted with two Zeeman sextets and one doublet. The variation in the Mössbauer parameters and the absorption area ratio indicated a cation distribution of (Co0.2-0.2xGaxFe0.8-0.6x)[Co0.8+0.2xFe1.2-0.4x]O4, and the magnetic behavior of the samples suggested that the increase in gallium content led to a decrease in the saturation magnetization and in the coercivity.