Magnetic Properties and Associated Microstructure of Zinc‐Bearing Square‐Loop Ferrites

Zinc oxide was added to square‐loop ferrite compositions in order to obtain a lower coercive force and higher magnetic saturation induction than that usually possible from standard commercial square‐loop ferrites. Curie temperatures, hysteresis loops, initial permeabilities, magnetization curves, and switching times for these zinc‐bearing square‐loop ferrites were determined, and representative curves of these parameters are given. Grain structure and etchpit density were also studied, and typical photomicrographs are presented. Zinc oxide can be added to square‐loop ferrites to great advantage, but if too much is added, the useful magnetic properties degenerate completely.