Abstract
The experiment was carried out to investigate the effect of changing mole ratio, n (= Fe3+/Co2+), and pH conditions on magnetic and physical properties of Co ferrite prepared by the chemical coprecipitation method without post-annealing. The chemical coprecipitation compositions were chosen according to the formula (CoO)·n/2(Fe2O3), where n varied between 2.0 and 3.5. Optimum magnetic properties were achieved with materials of composition (CoO)·1.375(Fe2O3). The typical magnetic and physical properties are saturation magnetization σs = 61.6×10-6 Wb·m/kg (49.0 emu/g), coercivity HcJ = 255 kA/m (3.21 kOe), lattice constant a = 0.8391 nm, and average particle size D = 23 nm, anisotropy constant K1 = +2.7×104 J/m3 (+2.7×105 erg/cm3), K2 = −13.0×104 J/m3 (−13.0×105 erg/cm3), anisotropy field HA nearly equals 3 MA/m (37.7 kOe). The rotational hysteresis integral Rh, which is related to the magnetization mechanism of these fine particles, is 1.32, and it was found that the magnetization mechanism is an incoherent one.
