Structural and Magnetic Properties of Mn^3+ Substituted Ordered and Disordered Li0.5Cr0.5Fe2O4 Nanoparticles.

A series of Li0.5MnxCr0.5Fe2 - xO4 (x = 0.0\--1 in the steps of 0.25) were synthesized by sol-gel auto combustion method, aiming to study the structural, magnetic and dielectric properties of ordered and disordered Li-ferrite related to the concentration of the substituted Mn^3+ ions. X-ray diffraction measurements were used for analyzing the structural parameters of the prepared samples. Superstructure lines are observed for Li0.5Cr0.5Fe2O4 and disappear at higher levels of Mn^3+ substitution. TEM images demonstrate that the particle size is uniform and are in good crystalline form. Saturation magnetization decreased from 51 to 24 emu/g, whereas coercivity varies from 90–170 Oe with Mn^3+ substitution. Permeability measurements were carried out as a function of temperature. Initial permeability (\mui) decreased with the increasing Mn^3+ substitution. The dc resistivity increased with the Mn^3+ substitution. Dielectric constant decreased with the increasing frequency and it also decreased with the increasing Mn^3+ substitution. [ABSTRACT FROM AUTHOR]