Zn- and Cu-substituted Co₂Y hexagonal ferrites: Sintering behavior and permeability

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• 作者：S. Bierlich ; J. Tö ; pfer ; ^{joerg.toepfer@fh-jena.de}
• 关键词：Hexagonal ferrite ; Y-type ferrite ; Multilayer inductor ; Permeability
• 刊名：Journal of Magnetism and Magnetic Materials
• 出版年：2012
• 期刊代码：31_03048853
• 类别：ph
• 出版时间：May, 2012
• 卷：324
• 期：10
• 页码：1804-1808
• 文件大小：786 K

摘要

Y-type polycrystalline hexagonal ferrites Ba₂Co_{2鈭?em>x鈭?em>y}Zn_xCu_yFe₁₂O₂₂ with 0鈮?em>x鈮? and 0鈮?em>y鈮?.8 were prepared by the mixed-oxide route. Single phase Y-type ferrite powders were obtained after calcinations at 1000 掳C. Samples sintered at 1200 掳C show a permeability that increases with the substitution of Zn for Co and display maximum permeability of 渭鈥?35 at 1 MHz for x=1.6 and y=0.4. A resonance frequency f_r=500 MHz is observed for Zn-rich ferrites with y=0 and 0.4. The saturation magnetization increases with substitution of Zn for Co. Addition of Bi₂O₃ shifts the temperature of maximum shrinkage down to T鈮?50 掳C. Moreover, an increase of the Cu-concentration further lowers the sintering temperature to T鈮?00 掳C, enabling co-firing of the ferrites with Ag metallization for multilayer technologies. However, low-temperature firing reduces the permeability to 渭鈥?10 and the resonance frequency is shifted to 1 GHz. Thus substituted hexagonal Y-type ferrites can be used as soft magnetic materials for multilayer inductors for high frequency applications.