Microstructure, Electrical, and Magnetic Properties of ZrO$_{2}$ Added MnZn Ferrites

We investigated the influence of ZrO
₂
on the microstructure and electromagnetic properties of MnZn ferrites by characterizing fracture surface micrographs, magnetic properties, and dc resistivity. Powders of Mn
_0.68
Zn
_0.25
Fe
_2.07
O
₄
composition were prepared by the conventional ceramic technique. Toroidal cores were sintered at 1350degC for 4 h in N
₂
/O
₂
atmosphere with 4% oxygen. The results show that the lattice constant and average grain size increase with ZrO
₂
concentration, but excessive ZrO
₂
concentration will result in exaggerated grain growth and porosity increase. The dc resistivity, activation energy, saturation magnetic flux density, and initial magnetic permeability increase monotonically when the ZrO
₂
concentration is not more than 0.04 wt% and then decrease with further increase of ZrO
₂
concentration. On the other hand, the porosity, drift mobility, resonance frequency, and core loss decrease initially and then increase with the increase of ZrO
₂
concentration.