Fabrication of SrFe12−x Ni x O19 nanoparticles and investigation on their structural, magnetic and dielectric properties

Abstract

SrFe12−x Ni x O19 nanoparticles (x = 0–1) were synthesized by a combustion sol–gel method. Their structure, dielectric and magnetic properties were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), an LCR metry, and vibrating sample magnetometry (VSM).The results reveal that all samples of Ni doped compounds (SrFe12−x Ni x O19) with x < 0.2 are single phase. It appears that the Fe3+ ions are substituted by Ni2+ ions on the crystallographic sites of the SrFe12O19 structure; however, for x ≥ 0.2, the secondary Ni phase ferrite (NiFe2O3) appears, which reduces the saturation magnetization and coercivity. In addition, Ni doping reduces the dielectric constant, dielectric loss, and alternating current (ac) electrical conductivity of the samples. The variation in ac conductivity (σ ac) with frequency shows that the electrical conductivity in these ferrites is mainly attributed to the electron hopping mechanism.Therefore; all the single-phase Ni doped samples are suitable for use in magnetic recording media and microwave devices.