Micromagnetic simulation on magnetic properties of Nd₂Fe₁₄B/α-Fe nanocomposites with Fe nanowires as the soft phase

Abstract

Fe nanowire array with strong shape anisotropy was employed as the soft phase in Nd–Fe–B based nanocomposites. The effects of the Fe nanowire distribution on magnetic properties of the nanocomposites were investigated by micromagnetic simulation. The results indicate that the shape anisotropy of Fe wires added in the same direction as the uniaxial magnetocrystalline anisotropy of the hard phase cannot increase the coercivity of the nanocomposite. When the nanowires are distributed perpendicular to the easy axis of the hard phase, the shape anisotropy of soft phase can retard the moments from rotating to the full reversed direction, leading to enhanced coercivity. In addition, with increasing the nanowire diameter, the coercivity of the nanocomposite decreases, but the dipolar interaction shows different roles in magnetic reversal of nanocomposite for different distributions of nanowires. The current results suggest that the coercivity of the Nd₂Fe₁₄B/α-Fe nanocomposite can be enhanced by introducing the soft magnetic nanowire array with the diameter less than the exchange length and with the long axis along the direction other than the easy axis of hard phase.

Keywords

Nd₂Fe₁₄B/α-Fe nanocomposite / micromagnetic simulation / Fe nanowires / shape anisotropy / exchange coupling

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Acknowledgements

This work was supported by the National Natural Science Foundation of China (Grant No. 51774146), the Guangdong Provincial Science and Technology Program (Grant no. 2015B010105008), the Guangzhou Municipal Science and Technology Program (Grant No. 201707010161), and the Fundamental Research Funds for Central Universities (Grant No. 2015ZP030).

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2018 Higher Education Press and Springer-Verlag GmbH Germany, part of Springer Nature