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Title: Advances in nanostructured permanent magnets research

Abstract

This paper reviews recent developments in research in nanostructured permanent magnets ( hard magnetic materials) with emphasis on bottom-up approaches to fabrication of hard/soft nanocomposite bulk magnets. Theoretical and experimental findings on the effects of soft phase and interface conditions on interphase exchange interactions are given. Synthesis techniques for hard magnetic nanoparticles, including chemical solution methods, surfactant-assisted ball milling and other physical deposition methods are reviewed. Processing and magnetic properties of warm compacted and plastically deformed bulk magnets with nanocrystalline morphology are discussed. Prospects of producing bulk anisotropic hard/soft nanocomposite magnets are presented.

Authors:
;
Publication Date:
Sponsoring Org.:
USDOE Advanced Research Projects Agency - Energy (ARPA-E)
OSTI Identifier:
1211366
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Physics. D, Applied Physics; Journal Volume: 46; Journal Issue: 4
Country of Publication:
United States
Language:
English

Citation Formats

Poudyal, N, and Liu, JP. Advances in nanostructured permanent magnets research. United States: N. p., 2012. Web. doi:10.1088/0022-3727/46/4/043001.
Poudyal, N, & Liu, JP. Advances in nanostructured permanent magnets research. United States. doi:10.1088/0022-3727/46/4/043001.
Poudyal, N, and Liu, JP. 2012. "Advances in nanostructured permanent magnets research". United States. doi:10.1088/0022-3727/46/4/043001.
@article{osti_1211366,
title = {Advances in nanostructured permanent magnets research},
author = {Poudyal, N and Liu, JP},
abstractNote = {This paper reviews recent developments in research in nanostructured permanent magnets ( hard magnetic materials) with emphasis on bottom-up approaches to fabrication of hard/soft nanocomposite bulk magnets. Theoretical and experimental findings on the effects of soft phase and interface conditions on interphase exchange interactions are given. Synthesis techniques for hard magnetic nanoparticles, including chemical solution methods, surfactant-assisted ball milling and other physical deposition methods are reviewed. Processing and magnetic properties of warm compacted and plastically deformed bulk magnets with nanocrystalline morphology are discussed. Prospects of producing bulk anisotropic hard/soft nanocomposite magnets are presented.},
doi = {10.1088/0022-3727/46/4/043001},
journal = {Journal of Physics. D, Applied Physics},
number = 4,
volume = 46,
place = {United States},
year = 2012,
month =
}
  • The present viewpoint set is on development of nanocomposite permanent magnets. A persistent theme is that such materials are inherently multiphase and interdispersed on the nanoscale, and that major improvements are indeed possible and accessible.
  • Here, we present a method, supported by theoretical analysis, for optimizing the usage of the critical rare earth element dysprosium in Nd 2Fe 14B (NdFeB)-based permanent magnets. In this method, we use Dy selectively in locations such as magnet edges and faces, where demagnetization factors are most significant, rather than uniformly throughout the bulk sample. A 200 nm thick Dy film was sputtered onto commercial N-38, NdFeB magnets with a thickness of 3 mm and post-annealed at temperatures from 600 - 700 C. Magnets displayed enhanced coercivities after post-annealing. Furthermore, our experimental results indicate as large as a 5 percentmore » increase in the energy product of NdFeB magnets, achieved for a total Dy weight percentage of 0.06 percent, much less than that used in commercial grade Dy-NdFeB magnets. Finally, by assuming all Dy diffused into NdFeB magnets, the improvement in energy product corresponds to a saving of over 1% Dy (critical element). Magnets manufactured using this technique will therefore be higher performing and significantly less expensive than those made presently.« less
  • We present a method, supported by theoretical analysis, for optimizing the usage of the critical rare earth element dysprosium in (NdFeB)-based permanent magnets. In this method, we use Dy selectively in locations such as magnet edges and faces, where demagnetization factors are largest, rather than uniformly throughout the bulk sample. A200 nm thick Dy film was sputtered onto a commercial N-38, NdFeB magnets with a thickness of 3 mm and post-annealed at temperatures from . Magnets displayed enhanced coercivities after post-annealing and as much as a 5 % increase in the energy product, while requiring a total Dy content ofmore » 0.06 wt. % - a small fraction of that used in the commercial grade Dy-NdFeB magnets. By assuming all Dy diffused into NdFeB magnets, the improvement in energy product corresponds to a saving of over 1% Dy (critical element). Magnets manufactured using this technique will therefore be higher performing which would potentially broaden the application space of these magnets in the traction motors of hybrid and pure electric vehicles, and wind generators.« less