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Nano Research 2020, 13(4): 1141-1148 https://doi.org/10.1007/s12274-020-2761-5
Research Article | Issue | Published: 07 April 2020

Chemical synthesis and coercivity enhancement of Nd2Fe14B nanostructures mediated by non-magnetic layer

Show Author's Information Kai Zhu1,2,  Junjie Xu1,  Xiaobai Wang1,  Wei Li1,  Kesong Tian1,  Yanglong Hou1,2( )
Beijing Key Laboratory for Magnetoelectric Materials and Devices (BKLMMD), Beijing Innovation Centre for Engineering Science and Advanced Technology, Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China
Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
Keywords:
grain boundary, graphene oxide, Nd2Fe14B nanostructures, chemical reduction, diffusion process, coercivity enchantment
Topics:
Ball millingGrain boundariesGrapheneIron compoundsMagnetic materials MagnetsNanomagnaticsNanostructures
Cite this article:
Zhu K, Xu J, Wang X, et al. Chemical synthesis and coercivity enhancement of Nd2Fe14B nanostructures mediated by non-magnetic layer. Nano Research, 2020, 13(4): 1141-1148. https://doi.org/10.1007/s12274-020-2761-5
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Abstract Full text Electronic supplementary material About this article

High-performance Nd2Fe14B magnets have been widely required in various fields recently due to the lightweight and miniaturization of devices. In this work, we synthesize Nd2Fe14B nanostructures with tunable magnetic properties through surfactant-assisted high energy ball milling (SAHEBM) process, achieving prominently enhanced coercivity by forming non-magnetic layers as grain boundary phase. When the reduction annealing process was carried out as pellet with Ca, the coercivity increased from 0.8 kOe to over 3 kOe as Nd2Fe14B powder, which is proved to be the contribution of the chemical diffusion of Nd elements and the formation of Nd-rich layer as magnetic insulating medium. In addition, two-dimensional graphene oxide (GO) was employed to build extra grain boundary, by which the coercivity of the core@dual-shell structure can achieve up to 8 kOe, tenfold of the original sample. The intrinsic mechanism indicated that the Nd-diffusion induced Nd-rich phase along with the reduced GO in the system could form non-magnetic layer as grain boundary and magnetically isolate the adjacent grains, significantly enhancing the exchange coupling effect. This work markedly opens up an effective approach for the chemical preparation of high-performance Nd2Fe14B nanostructured magnets, especially after post treatment, and gives an insight on the interactions at nanoscale.


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Electronic supplementary material
About this article

Chemical synthesis and coercivity enhancement of Nd2Fe14B nanostructures mediated by non-magnetic layer

Show Author's information Kai Zhu1,2, Junjie Xu1, Xiaobai Wang1, Wei Li1, Kesong Tian1, Yanglong Hou1,2( )
Beijing Key Laboratory for Magnetoelectric Materials and Devices (BKLMMD), Beijing Innovation Centre for Engineering Science and Advanced Technology, Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China
Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China

Abstract

High-performance Nd2Fe14B magnets have been widely required in various fields recently due to the lightweight and miniaturization of devices. In this work, we synthesize Nd2Fe14B nanostructures with tunable magnetic properties through surfactant-assisted high energy ball milling (SAHEBM) process, achieving prominently enhanced coercivity by forming non-magnetic layers as grain boundary phase. When the reduction annealing process was carried out as pellet with Ca, the coercivity increased from 0.8 kOe to over 3 kOe as Nd2Fe14B powder, which is proved to be the contribution of the chemical diffusion of Nd elements and the formation of Nd-rich layer as magnetic insulating medium. In addition, two-dimensional graphene oxide (GO) was employed to build extra grain boundary, by which the coercivity of the core@dual-shell structure can achieve up to 8 kOe, tenfold of the original sample. The intrinsic mechanism indicated that the Nd-diffusion induced Nd-rich phase along with the reduced GO in the system could form non-magnetic layer as grain boundary and magnetically isolate the adjacent grains, significantly enhancing the exchange coupling effect. This work markedly opens up an effective approach for the chemical preparation of high-performance Nd2Fe14B nanostructured magnets, especially after post treatment, and gives an insight on the interactions at nanoscale.

Keywords: grain boundary, graphene oxide, Nd2Fe14B nanostructures, chemical reduction, diffusion process, coercivity enchantment

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Publication history
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Acknowledgements

Publication history

Received: 20 January 2020
Revised: 29 February 2020
Accepted: 15 March 2020
Published: 07 April 2020
Issue date: April 2020

Copyright

© Tsinghua University Press and Springer-Verlag GmbH Germany, part of Springer Nature 2020

Acknowledgements

This work was supported by the National Natural Science Foundation of China (Nos. 51590882, 51631001 and 51672010), and the National Key R&D Program of China (No. 2017YFA0206301).

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