Rare-earth (La~(3+)) substitution induced changes in the structural, dielectric and magnetic properties of nano-CoFe_2O_4 for high-frequency and magneto-recording devices

摘要

Influence of Fe substitutions by rare-earth (La3+) ions on structural, electric, dielectric and magnetic properties of cobalt ferrite employing glycine nitrate method is investigated. The FTIR spectra and Mossbauer spectroscopy measurements illustrate spinel phase formation of CoFe2-xLaxO4 nanoferrites supporting structural analysis from X-ray diffraction patterns. Magnetic analysis revealed that with increasing La concentration to 0.1, the coercivity and squareness values increased from 1958 to 3312 Oe, and 0.52-0.57, respectively. To obtain accuracy in the saturation magnetization values, a theoretical approach was used considering the ferromagnetic (FM) and antiferromagnetic/paramagnetic (AFM/PM) components. Dielectric measurements studied in the range of 100 Hz-1 MHz frequency from room temperature to 300 degrees C indicated enhanced dielectric constant with low loss on increasing La3+ concentration. The ferrite nanoparticles with improved magnetic and dielectric properties make these materials suitable for magneto-recording and high-frequency devices.