Structural, spectral, magnetic and dielectric properties of Bi substituted Li-Co spinel ferrites

Abstract Bismuth (Bi) substituted lithium-cobalt ferrites with compositions LiCo0.5BixFe2-xO4 (0.0 ≤ x ≤ 0.4) were synthesized via micro emulsion method. The spinel structure was confirmed by XRD analysis. Lattice constant and X-ray density were increased from 8.384 A to 8.397 A and 4.78-6.13 (gm/cm3) respectively with the increase of bismuth contents. FTIR spectra of bismuth substituted LiCo0.5Fe2O4 ferrites indicated that tetrahedral bands were in the range 500-600 cm−1 which revealed the spinel structure of synthesized ferrites. Saturation magnetization (Ms) increased from 2.79 to 14.95 (emu/g) with the substitution of bismuth ions. The frequency dependent dielectric parameters i.e dielectric constant (e′) and dielectric loss (e′′) were elucidated in the frequency range of 1 MHz - 3 GHz. The value of e′ and e′′ decreases with the increase of frequency. The increase in the value of saturation magnetization and decrease in the value of coercivity suggested that bismuth substituted LiCo0.5Fe2O4 ferrites might be potential candidate for high density recording media applications.