The magnetic properties of Rockets the U-type ferrite synthesized by a sol-gel process had studied by substituting cobalt with manganese or zinc in cobalt-based U-type ferrite.The substituted U-type ferrite showed a dominant crystal structure at a different substitution ratio of manganese and zinc.The change of the starting temperature of U-type ferrite formation according to substitutional elements was confirmed by TG-DTA analysis.In the case of manganese substitution, the starting temperature of U-type ferrite formation lowered, and on the contrary, when zinc was substituted, it became higher.
The magnetic properties of the U-type ferrite substituted with manganese showed a tendency that the saturation magnetization was decreased and the coercivity Hoodie was increased as the manganese ratio increased.The highest saturation magnetization was 57.9 emu/g in the specific composition (Ba4Co0.5Zn1.
5Fe36O60) substituted with zinc.