Characterization and magnetic exchange observation for CoFe₂O₄–CoFe₂ nanocomposite microfibers

Author： Guo Liping Shen Xiangqian Song Fuzhan Liu Mingquan Zhu Yongwei

ISSN： 0928-0707

Source： Journal of Sol-Gel Science and Technology, Vol.58, Iss.2, 2011-05, pp. : 524-529

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Abstract

The magnetic hard-soft CoFe₂O₄–CoFe₂ nanocomposite microfibers have been synthesized by the sol–gel and partial reduction process, where CoFe₂O₄ ferrite is the hard phase with a grain size range from 43 to 62 nm and CoFe₂ alloy the soft phase with grain sizes around 30 nm. These nanocomposite microfibers exhibit the magnetization behavior like a single phase magnetic material, and the magnetic exchange coupling effects are observed between the hard and soft phases. The specific saturation magnetization of CoFe₂O₄–CoFe₂ nanocomposite microfibers shows an increase tendency with the increasing weight fraction of CoFe₂, while the coercivity is consequently reduced. The nanocomposite microfibers have a maximum remanence 51.7 Am²/kg when the phase contents of CoFe₂ around 28 wt% and CoFe₂O₄ about 72 wt%.