A study of the properties of SrFe12−xCoxO19 nanoparticles

In this paper, the nanoparticles of SrFe12−xCoxO19 (x=0-2) were synthesized via the sol-gel technique. The XRD results showed that all samples with x≤0.5 are single-phase. It seems that the Fe3+ ions are substituted by Co2+ ions in the crystallography sites of the SrFe12O19 structure, but for the x>0.5 cases, the phase of CoFe2O4 is materialized in the samples. The DC electrical resistivity decreases with the increase of cobalt content up to level of x=0.5, but it increases on further addition of cobalt. We found that the dielectric constant and the dielectric loss for samples with x=1 and 1.2 into the pure sample (SrFe12O19), decrease as the Co2+ content increases. The variation of AC conductivity (σac) with frequency ranging from 500 Hz to 200 KHz shows that electrical conductivity in these ferrites is mainly due to the electron hopping mechanism.