Shuiyuan Su

Synthesis of Cu-modified Co2Z hexaferrite with planar structure by a citrate precursor method

Abstract Co2Z hexaferrite is a planar anisotropic iron oxide which can present high values of permeability at high frequency. In this paper, Cu-modified Co2Z hexaferrites powders were synthesized at a low temperature using a citrate precursor method. The formation of Z-type phases was characterized by X-ray diffraction and magnetization measurements. It is found that phase formation temperature and sintering temperature were influenced directly by the content of copper. The effects of Cu-substitution on the microstructure and high frequency properties of the ceramics have been investigated.

Preparation and magnetic characterization of the ferroxplana ferrites Ba3Co2−xZnxFe24O41

Abstract Ferroxplana ferrites Ba 3 Co 2− x Zn x Fe 24 O 41 ( X =0–1.0) were prepared by a citrate precursor method. X-ray diffraction analysis indicated that single Z-type phase was obtained at a relatively low temperature between 1150°C and 1200°C and no appreciable secondary phase was found. The substitution of Co with Zn caused an increase in the saturation magnetization and a decrease of the Curie temperature. The influences of Zn-substitution on the microstructure and high-frequency properties of the ceramics were investigated. The materials exhibited excellent high-frequency properties.

Effect of Copper Substitution on the Dielectric and Magnetic Properties of Low-Temperature-Sintered Z-type Ferrites.

Cu-substituted Z-type ferrite (Ba3Co2-xCuxFe24O41, where X=0, 0.2, 0.4, 0.6 and 0.8) powders were synthesized using a citrate precursor method. Single Z-type phases were found by X-ray diffraction to form at a relatively low temperature of 1100–1150°C. With an appropriate sintering aid, highly dense Cu-substituted ceramics could be obtained after sintering below 900°C and these exhibited excellent electromagnetic properties such as high initial permeability up to 7.0 with high cutoff frequencies above 1.2 GHz. The Cu content in the composition has a significant influence not only on the magnetic properties but also on the dielectric properties of the sintered ceramics. In this paper, the effects of copper substitution on the microstructures and properties of the low-temperature-sintered Ba3Co2-xCuxFe24O41 are investigated and discussed. The dielectric constant increases with increasing Cu content, which is explained by the presence of two types of charge carriers.