Abstract
This experiment was carried out to investigate the effect of ZnO substitution on the magnetic and physical properties of Co-Ni ferrite fine particle prepared by the chemical coprecipitation method without post-annealing process. The chemical coprecipitation compositions were chosen according to the formula (CoO)0.5(NiO)0.5-x(ZnO)x⋅n/2(Fe2O3), where x was varied between 0 and 0.5, and n between 2.0 and 3.0. The saturation magnetization σs, has a tendency to increase up to x=0.3, however decrease when x is above 0.3. On the other hand, the coercivity HcJ decreases as x increases. Optimum magnetic properties were achieved with materials of composition (CoO)0.05(NiO)0.45(ZnO)0.05⋅1.25(Fe2O3). The typical magnetic and physical properties are saturation magnetization σs=61.9×10-6 Wb⋅m/kg (49.3 emu/g), coercivity HcJ=372.5kA/m (4.68 kOe), the lattice constant a= 0.8379 run, and the average particle size = 38 nm. The rotational hysteresis integral Rh, which is related to the magnetization mechanism of these fine particles, is 1.80, and it is found that the magnetization mechanism is an incoherent rotation mode. Crystalline magnetic anisotropy constants are K11=+6.7×104 J/m3 (+6.7×105 erg /cm3) and K2=-16.8×104J/m3 (-16.8×105 erg/cm3).
