Magnetic Properties of Ni-Cu-Zn Ferrites with Co Substitution

Single‐phase polycrystalline Ni0.85−x−yCu0.15Znx Coy Fe2O4 (x = 0.2, 0.4, 0.6; y = 0, 0,02, 004, 006) were synthesized by a standard ceramic technology. The mean particle sizes range between 2 and 30 μm. The main magnetic parameters such as saturation magnetization, remanence and coercivity were obtained from the entire hysteresis loops plotted in AC (2 kHz) magnetic field at room temperature. Saturation magnetization decreases slightly with increasing Co‐concentration for x = 0.2, 0.4 only. The remanence decreases with increasing Co‐concentration for all the compounds, but the coercivity is practically constant for most of the samples. Hysteresis losses were evaluated from the hysteresis loops by using the Fourier decomposition. The initial permeabilities were obtained from the minor hysteresis loops in low enough fields. It was found that: only for x = 0.4 and y = 0.04, the initial permeability increases, hysteresis losses decrease and the changes of other magnetic parameters are negligible.