Low temperature synthesis of Li0.5ZrxCoxFe2.5−2xO4 powder and their characterizations

Lithium–zirconium–cobalt ferrites bearing the chemical formula Li0.5ZrxCoxFe2.5−2xO4 for x ranging from 0.0 to 0.5 with the step increment of 0.1 were synthesized by the sol–gel auto combustion technique. The variation of ZrCo substitution has a significant effect on the structural, electrical and magnetic properties of lithium ferrite. Lattice parameters ‘a’ increased from 8.331 to 8.358Å. Cation distribution data suggest that Co2+ and Li+ show marked preference for octahedral B-site, whereas Zr4+ and Fe3+ occupy both the available sites. The IR spectra show two major absorption bands related to the spinel structure of ferrite. Saturation magnetization decreased whereas coercivity increased with the increase in ZrCo substitution. Resistivity and activation energy increased whereas dielectric constant decreased with the increase in ZrCo substitution. Dielectric constant increased with the increase in temperature from 403 to 773K at a constant frequency of 1kHz. The possible reasons responsible for the changes in structural, electrical and magnetic properties with the increase in ZrCo substitution are undertaken. Superstructure peaks were observed in the XRD pattern. The superstructure peaks are evidence that sample (x=0.0) has an ordered spinel type structure. These superstructure peaks arise from the ordering of the lithium sublattice. These peaks were disappeared for Zr4+ and Co2+ co-substitution indicating that structure is changed from ordered to disordered lithium ferrite. [Display omitted] ► Zr4+ and Co2+ co-substituted Li0.5Fe2.5O4. ► Crystallite size decreased with Zr4+ and Co2+ co-substitution. ► Ms decreased whereas Hc increased with Zr4+ and Co2+ co-substitution. ► Resistivity and dielectric constant shows inverse trend to each other.