Effects of co-dopants on the magnetic properties of Ni-Zn ferrites

In this study, substitution of co-dopants into the Ni0.4Zn0.6Fe2O4 ceramic was performed. Al3+, Sn4+ and Ti4+ ions were added to the Ni0.4Zn0.4Li0.10Fe2.10O4 ceramic to improve magnetic properties. After sintering, all samples were indexed on a spinel structure and no detectable second phase was observed. When the concentration of dopants increased, the grain size of the Ni-Zn ferrites increased from 1.40 to 6.05 μm and the saturation magnetization declined from 428.8 emu/cm3 to 374.0 emu/cm3. Amongst the systems investigated, the Ni0.4Zn0.4Li0.10Al0.050Fe2.050O4, Ni0.4Zn0.425Li0.10Ti0.025Fe2.050O4, and Ni0.4Zn0.450Li0.10Ti0.050Fe2.000O4 ceramics revealed promising magnetic properties for applications. The measured initial permeability and quality factor were respectively 291.9 and 45.1 for the Ni0.4Zn0.4Li0.10Al0.050Fe2.050O4 ceramic, 316.9 and 42.5 for the Ni0.4Zn0.425Li0.10Ti0.025Fe2.050O4 ceramic, 429.4 and 34.8 for the Ni0.4Zn0.450Li0.10Ti0.050Fe2.000O4 ceramic. The high initial permeability and quality factor values associated with good electrical resistivity (>106 Ω-cm) qualify the ceramics for high frequency applications.