Structural, magnetic and electrical properties of CoSi ferrites synthesized by sol-gel self-propagating method

Abstract

CoFe2O4 is mainly used in magnetic strain sensor, magnetic resonance imaging, supercapacitor, cryogen, high density magnetic recording medium and magneto-optical devices and so on. In this study, SixCo1-xFe2O4 (where x = 0, 0.05, 0.10, 0.15, 0.30, 0.40, 0.50) ferrites were prepared by sol-gel self-propagating method, and the effects of different amount of silicon substitution on the properties of cobalt ferrite were studied. The X-ray diffraction spectrums demonstrate that the secondary phase Fe2O3, Fe2·56Si0·44O4 and FeO appear when x ≥ 0.15. The SEM images of the samples show that with the increase of silicon ion content, the porosity of cobalt ferrite increases and the sintering density decreases. The substitution of silicon significantly changed the electromagnetic properties of Co ferrite samples. Fortunately, the coercive force (Hc) increased. Moreover, the dielectric constant raised initially when 0 ≤ x ≤ 0.30 and then reduced when 0.30 <x ≤ 0.50 with the increasing Si substitution at low frequency, which achieves the maximum at x = 0.30.