Impact of ZrO2 additive on the microstructure, magnetic properties, and temperature dependence of the initial permeability of LiTiZn ferrite ceramics

Abstract

The effect of the diamagnetic ZrO2 addition on the microstructure and magnetic properties of LiTiZn ferrite ceramics, including the shape and parameters of the temperature dependence of the initial permeability, has been investigated. The defect structure of ferrite ceramic samples is assessed according to our earlier proposed method based on the mathematical treatment of the experimental temperature dependencies of the initial permeability. It was found that the defect structure of ferrite ceramics increased by 350% with an increase in the concentration of the ZrO2 additive in the range of (0–0.5) wt.%. In this case, for the same samples, the increase in the true physical broadening of diffraction peaks is only 20%, and the coercive force by 50%. Simultaneously, the maximum of the experimental temperature dependence of the initial permeability dropped by 45%. The microstructure of all samples is characterized with a similar average grain size according to the SEM data. However, samples with 0.5 wt.% of ZrO2 are characterized by the formation of conglomerates. A linear relationship was obtained between the defect structure and the width of the diffraction peaks, which indicates that this parameter is related to the elastic stress of ferrite ceramics. These results suggest that the high sensitive proposed method can be recommended for impurity and defect monitoring of soft ferrite products.