Phase Formation, Sintering Behavior, and Magnetic Properties of Low-Temperature Fired Mg-Cu-Zn Ferrites

摘要

The phase formation, sintering behavior, and magnetic properties of Mg-Cu-Zn ferrites with composition Mg_(1-x-y) Cu_yZn_(x+z)Fe_(2_z)O_(4-z/2) with 0.4 ≤ x ≤ 0.8; 0 ≤ y ≤ 0.35; and 0 ≤ z ≤ 0.06 were investigated. Ferrite formation from starting oxides is complete at 900℃. To guarantee sufficient densifkation at 900℃ substoichiometric compositions with small iron deficiency z = 0.02 are required. Substitution of Cu for Mg with 0 ≤ y ≤ 0.35 in a ferrite with x = 0.5 has minor effect on permeability only; however, the shrinkage is significantly shifted to temperatures as low as T < 900℃. The permeability is mainly governed by the Zn concentration; u increases from μ = 200 to 700 as x increases from x = 0.4 to 0.6, whereas simultaneously the Curie temperature is reduced from 180℃ to 40℃, respectively. Mg-Cu-Zn ferrites represent an interesting alternative to Ni-Cu-Zn ferrites with large potential for multilayer applications.