Crystallographic and Magnetic Properties of Vanadium-substituted Li-Co-Ti Ferrite

The crystallographic and magnetic properties of vanadium-substituted lithium cobalt titanium ferrite, Li0.5+xCo0.2Ti0.2VxFe2.1−2xO4, are investigated. Ferrite was replaced with vanadium in the range of 0.00 to 0.20 in steps of 0.05 and was synthesized by using conventional ceramic methods. Using X-ray diffraction and Mossbauer spectroscopy, the formation of crystallized particles was confirmed in Li0.5+xCo0.2Ti0.2VxFe2.1−2xO4 ferrite powders. All of the samples showed a single phase with a spinel structure, and the lattice parameters were nearly constant as the substituted content increased. The average grain size of the samples increased with x. For x = 0 in Li0.5+xCo0.2Ti0.2VxFe2.1−2xO4, the Mossbauer spectrum could be fitted with two Zeeman sextets, which is the typical spinel ferrite spectra of Fe with A and B sites. However, for x ≥ 0.05, the Mossbauer spectra could be fitted with two Zeeman sextets and one doublet. From the variations of the Mossbauer parameters and the absorption area ratio, the cation distribution could be determined as (Co0.2−δVx−δFe0.8−x+2δ)[Li0.5+xCoδVδTi0.2Fe1.3−x−2δ]O4. The magnetic behavior of the samples showed that an increase in the vanadium content led to an increase in the saturation magnetization and then to some decrease whereas the coercivity decreased. The maximum saturation magnetization was 44.81 emu/g at x = 0.05, and the maximum coercivity was 120.4 Oe at x = 0.