Effect of lightly substituted samarium ions on the structural, optical, magnetic and dielectric properties of the sonochemically synthesized M-type Sr-hexaferrite nanoparticles

In this study, the role of sonochemical treatment followed by a combustion process adopted for the synthesis of SrSmxFe12-xO19 (x = 0.01 to 0.03) hexaferrites. We have investigated effect of lightly Sm substitutions on structural, magnetic, optical and dielectric properties in Strontium hexaferrites. X-ray diffraction analysis show M as major phase with impurity. The FTIR analysis shows that the value of force constant increased on both sides (tetra hederal and octa hederal) with the increase of samarium content. The band gap was calculated using Tauc method from UV–Visible spectra. Result shows that as the samarium content increases from x = 0.01 to 0.03 the band gap gradually increases from 2.50 eV 2.91 eV respectively. The surface morphology of prepared Sm substituted SrM nanoparticles was examined using field emission scanning electron microscopy, an average particle size was found to 301 nm, 254 nm, and 285 nm for x = 0.01, 0.02, and 0.03 compositions respectively. High values of Ms (53.104 emu/g.) and Mr (29.0 emu/g) observed in x = 0.03 sample with low Hc of 53.104 Oe. Mr/Ms values of all samples are >0.5 show that of formed hexaferrite nanoparticles possess single magnetic domain structure. The Sm-doped of the SrFe12O19 compound exhibits a low dielectric constant (ε′) ∼ 20 at low frequencies, while it increased with increasing temperature and reached 100 when the Sm content was 0.01, but less than 150 in x = 0.02 and 0.03. The temperature and frequency-dependent dielectric constant confirmed the contributions of different polarization mechanisms.