Modulation of physico-chemical, magnetic, microwave and electromagnetic properties of nanocrystalline strontium hexaferrite by Co-Zr doping synthesized using citrate precursor sol-gel method

Co-Zr doped SrCoxZrxFe(12−2x)O19 (x=0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) have been synthesized by citrate precursor sol-gel method. We have studied the impact of coupled substitution of magnetic Co2+ and non-magnetic Zr4+ for Fe3+ on the morphology, magnetic, microwave and electromagnetic properties of SrCoxZrxFe(12-2x)O19. Characterization of these materials has been done by XRD, FT-IR, EDS, TEM, VSM and Mössbauer spectroscopy techniques. Complex permeability (μ′), complex permittivity (ε′) and reflection loss curves have also been analyzed. XRD analysis indicates the formation of single phase hexagonal ferrites at a low temperature of 800 °C. Mössbauer spectra indicates that the dopant ions are located on the tetrahedral 4f1 and octahedral 4f2 sites up to x=0.4, octahedral 12k site and bipyramidal 2b site for x=0.6 and 12k site for x=0.8-1.0. The reflection loss (R.L.) analysis shows that all the ferrites (except x=0.2) have wide absorption bandwidth (R.L.<−10 dB for 2-3.5 GHz) with peaks of 90-99% absorption in 12.4-18 GHz band.