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Study on Crystal Structure and Magnetic Properties of Ba4Co2Fe36O60 by Sol-Gel Method

Jeong K.-P., Yang S.-W., Kim J.-G.

Archives of Metallurgy and Materials

2018

Vol. 63, iss. 3

1449--1452

U-type ferrite typified by Ba4Co2Fe36O60 is used as a RAM (Radar Absorbing Materials) in the X-band (8-12 GHz). Ba4Co2Fe36O60 is known to have a complex crystal structure, which makes it difficult to obtain single phase and have low reproducibility. Previously known U-type ferrites have been fabricated based on a ceramic process that mixing (by a ball mill), calcining, grinding, binder mixing, drying, sieving, pressing and sintering. In contrast, the process of preparing the powder by the sol-gel method and its heat-treating is advantageous in that it can reduce the process steps and the required time. In addition, the precise stoichiometric control by the sol-gel method can effectively evaluate the effect of added or substituted elements. In this study investigates the crystal structure of Ba4Co2Fe36O60 synthesized by the sol-gel method and the morphology of U-type ferrite nano-powders according to various heat treatment conditions. Analysis of the crystal structure is used for XRD. Morphology and size are observed by SEM. In addition, VSM is performed to confirm the change of magnetic properties according to various heat treatment conditions.

Influence of Substituted Elements on Reflection Loss of Ba-Ferrite Nanoparticle

Yang S., Jeong K.-P., Park S.-Y., Kim J.-G.

Archives of Metallurgy and Materials

2017

Vol. 62, iss. 2B

1201--1204

Due to the rapid development of the information communication industries, it is expected that next-generation mobile communication devices in the data communication environment will be used at the same time in the L~X band (1–12 GHz). To mutual electric wave interference prevention, research on wave absorbers in L~X band is needed. In this paper, barium ferrite was researched as L~X band wave absorber. The Barium ferrite (BaM, Ba ferrite) substituted by divalent ions (Co2+, Cu2+, Ni2+, Zn2+) and tetravalent ion (Ti4+). The substituted Ba ferrite nanoparticles were fabricated by sol-gel process. Lattice parameter, particle size, magnetic properties, and reflection loss were analyzed by X-ray diffraction (X-RD), a Vibrating Sample Magnetometer (VSM), and a Network Analyzer. Lattice parameter of Ba ferrite was changed 0.0005 to 0.0078 Å in a-b direction, and 0.0187 to0.0445 Å in c-direction by substituted elements, and it influenced on magnetic anisotropy. In addition, Co-Ti substitution elements influenced that coercive force decrease 5,739 to 2,240 Oe. Moreover, reflection loss frequencies were shifted from 16.3 GHz to 14.4 and 17.4 GHz by substituted elements Co-Ti and Zn-Ti.