Dynamics of electron density, and dielectric properties of CoFe2O4 nanoparticles influenced by substitution of La3+ at Fe3+

Abstract

Cobalt ferrite (CoFe2O4) has been subjected to the existence or nonexistence of ferroelectric properties. The nominal composition of CoLaxFe2-xO4 (where, x = 0, 0.05, 0.10, 0.15, 0.20, 0.25, and 0.30) has been synthesized by the sol-gel method. The synthesized grain sizes varied from 60 nm to 80 nm. The electron density plots obtained using Rietveld refinement of the x-ray diffraction data showed the displacement of the Co and Fe ions which is highly influenced by the substitution of La3+ at Fe3+. It is also observed that the AC conductivity increases with the increase of La3+ amount in the parent sample (CoFe2O4) which is dominated by frequency. The contribution of grain and grain boundaries on dielectric relaxation has been investigated at room temperature (25℃). The electric permittivity (ε) is also enhanced due to the substitution La3+ at Fe3+. Finally, the composition CoLa0.10Fe1.9O4 sintered at 900oC shows the highest electric permittivity (ε^' ) with low dielectric loss (tanδ) and finds a suitable application for the strain gauge, made by evaporating a small amount of metal onto the surface of a thin sheet of this material.