Structural, dielectric and magnetic properties of La substituted CoFe2O4 nanoparticles

Abstract

We report the effect of lanthanum (La3+) substitution on the physical properties of cobalt ferrite (CoFe2O4) magnetic nanoparticles by co-precipitation method. X-ray diffraction analysis reveals the formation of single phase cubic inverse spinel structure of CoFe2O4 and CoFe1.9La0.1O4, and CoFe2−xLaxO4 (0.2 < x < 0.5) with a mixed impurity phase, LaFeO3. Fourier transform infrared spectral analysis confirms the presence of Fe-O symmetrical stretching vibration at tetrahedral site. SEM studies reveal that the surface microstructure of CoFe2O4 nanoparticles was effectively modified by La3+ ion substitution. Energy dispersive spectral analysis confirms the presence of elements in the synthesized nanoparticles. Transmission electron microscopy studies reveal that the particle size increases with increasing La3+ ion concentrations. Dielectric properties reveal that the value of dielectric constant (ɛ′) and dielectric loss (ɛ″) are gradually increases with increasing La3+ ion concentration as well as temperature. Magnetic measurement reveals that the saturation magnetization decreases from 61.45 to 25.13 emu/g with increasing La3+ ion concentrations.