Optical, magnetic and ferroelectric properties of Ba0.2Cu0.8-xLaxFe2O4 (x=0.2-0.6) nanoparticles

The Ba0.2Cu0.8-xLaxFe2O4 (x = 0.2, 0.4 & 0.6) (BCLF) nanoparticles were prepared by hydrothermal method and further characterized for structural, morphological, optical, magnetic, and ferroelectric properties. The structural analysis was carried out using X-ray diffraction spectra. These results revealed that all the samples showed the presence of cubic spinel phases. The Fourier transform infrared (FTIR) studies expressed the formation of broad (v(1)) and narrow (v(2)) absorption bands which can reflect the arrangement of cations between tetrahedral (v(1)) and octahedral (v(2)) sites. The surface morphology was studied using the field emission scanning and transmission electron microscopes (FESEM & TEM). The FESEM pictures expressed the gradual formation of nanofibers with increase of La-content. The variation of optical bandgap (E-g similar to 1.96-2.15 eV) as a function of substituent concentration was elucidated. The magnetization versus applied magnetic field (M-H) loops of BCLF nanoparticles showed the superparamagnetic nature which can be useful for the biomedical applications. The cation distribution was made between the octahedral (B) and tetrahedral (A) sites using the Neel's two-sublattice model.