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Journal article
Exchange Bias in Bulk alpha-Fe/gamma-Fe70Mn30 Nanocomposites for Permanent Magnet Applications
ACS applied nano materials, v 2(4), pp 1940-1950
01 Apr 2019
Featured in Collection : UN Sustainable Development Goals @ Drexel
Abstract
Here we report on the microstructural factors influencing the formation of the interfacial exchange bias effect in three-dimensional transition-metal-based nanocomposite systems, with relevance to permanent magnet applications. Bulk phase-separated nanocomposites consisting of the ferromagnetic alpha-Fe and metastable antiferromagnetic gamma-Fe70Mn30 phases exhibit a notable low-temperature exchange bias and substantial coercivity (H-ex = 24.6 kA/m, H-C = 95.7 kA/m) as well as a near room-temperature blocking temperature. Structural investigation by synchrotron X-ray diffraction, neutron scattering, and transmission electron microscopy confirm that the ferromagnetic a-Fe phase nucleates as small precipitates (d approximate to 50 nm) at the grain boundaries of the antiferromagnetic gamma-Fe70Mn30 grains (d = 360-740 nm) and grows anisotropically upon heat treatment, resulting in an elliptical geometry. These results indicate that optimization of the exchange bias effect in bulk nanocomposite systems may be achieved through maximizing the surface-to-volume ratio of ferromagnetic precipitates in an antiferromagnetic matrix, enhancing the magnetocrystalline anisotropy of the antiferromagnetic phase to facilitate interfacial pinning and ensuring a balanced distribution of the ferromagnetic and antiferromagnetic phases. This work further clarifies critical factors influencing the formation of an exchange bias in an inexpensive transition-metal-based bulk nanocomposite system with potential for scalable production.
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Details
- Title
- Exchange Bias in Bulk alpha-Fe/gamma-Fe70Mn30 Nanocomposites for Permanent Magnet Applications
- Creators
- I. J. McDonald - Northeastern Univ, Dept Chem Engn, Boston, MA 02115 USAM. E. Jamer - NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USAK. L. Krycka - NIST Center for Neutron ResearchE. Anber - Drexel UniversityA. C. Lang - Drexel UniversityW. D. Ratcliff - NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USAD. Heiman - United States Naval AcademyM. L. Taheri - Drexel UniversityJ. A. Borchers - NIST Center for Neutron ResearchL. H. Lewis - Northeastern Univ, Dept Chem Engn, Boston, MA 02115 USA
- Publication Details
- ACS applied nano materials, v 2(4), pp 1940-1950
- Publisher
- American Chemical Society; Washington, DC
- Number of pages
- 21
- Grant note
- ECCS-1402738; DMR-1332208 / National Science Foundation; National Science Foundation (NSF) ARPA-E PNDIODES program N00014-10-1-0553 / Office of Naval Research grant; Office of Naval Research DMR-0520547 / NSF; National Science Foundation (NSF) 1429661 / NSF MRI award; National Science Foundation (NSF); NSF - Office of the Director (OD) 654000 / European Union's Horizon 2020 research and innovation programme under the SINE2020 project
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- [Retired Faculty]
- Web of Science ID
- WOS:000466443000020
- Scopus ID
- 2-s2.0-85078245288
- Other Identifier
- 991019169547204721
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- Collaboration types
- Domestic collaboration
- Web of Science research areas
- Materials Science, Multidisciplinary
- Nanoscience & Nanotechnology