Characterization and curve fittings of Mg+2 substituted R-type hexagonal ferrites

In the present investigation, the divalent basic element “Sr2+” was replaced with another divalent element “Mg2+” to understand the influential effect of Mg2+ on structural, electrical, dielectric and FTIR properties of Sr2+ based R-type hexagonal ferrites Sr1-xMgxFe4Sn2O11 with composition (x = 0.0, 0.1, 0.2, 0.3). The material was synthesized by sol-gel auto combustion method and sintered at 800 °C temperature for development of the required phase. The XRD and FTIR analysis revealed the formation of single-phase R-type hexagonal ferrites. It was observed that the values of lattice parameters a (Å), c (Å), crystallite size (nm), X-ray density (g/cm3) and unit cell volume V (Å)3 changed with Mg2+ substitution. The Scherer formula was used to find the crystallite size which varied in the range from 11 to 13 nm for all synthesized samples. The FTIR spectra also indicated the presence of negligible amount of moisture and Nitrogen in sample, absorbed from the atmosphere. The dielectric constant results showed the higher values for Mg2+ substituted samples than the pure sample. Furthermore, Debye function was used for the fitting of the dielectric constant results which indicated the participation of more than one ion in the increment of dielectric constant. The AC conductivity increased with the increase of frequency, consequently the experimental result was compared with theoretical results by Jonscher's power law which elicited the conduction mechanism. The P-E (polarization vs. electric field) loops substantiated the decrease in saturation and remnant polarization with Mg+2 content. The electrical resistivity of synthesized sample unveiled the resistive nature of sample significantly. It is suggested that the present R-type ferrites are useful in microwave absorption devices and in transformer to reduce the eddy current losses.