Magnetism of ultrathin intergranular boundary regions in Nd–Fe–B permanent magnets

Autor:	Y. Takeno, Yasukazu Murakami, Tsuyoshi Matsuda, Tadakatsu Ohkubo, Toshiaki Tanigaki, Daisuke Shindo, Hyun Soon Park, Takayoshi Sasaki, Kazuhiro Hono
Rok vydání:	2014
Předmět:	Materials science Polymers and Plastics Condensed matter physics Magnetism Metals and Alloys Coercivity Electron holography Electronic Optical and Magnetic Materials Amorphous solid Magnetic field Magnetization Magnet Ceramics and Composites Grain boundary
Zdroj:	Acta Materialia. 71:370-379
ISSN:	1359-6454
DOI:	10.1016/j.actamat.2014.03.013
Popis:	The magnetism of a thin grain-boundary (GB) phase that envelopes the Nd2Fe14B grains in optimally annealed Nd–Fe–B sintered magnets was investigated by electron holography. The phase shift measured from a thin-foil specimen containing a tilted amorphous GB phase (∼3 nm in width) was −0.34 rad, which is substantially smaller than that expected for the nonferromagnetic GB phase of −1.2 rad. Simulations of the phase shift with various magnetization values suggest that the magnetic flux density of the GB phase is ∼1.0 T. The observations imply significant exchange coupling between Nd2Fe14B grains, which can explain the avalanche propagation of magnetization reversal observed in sintered magnets.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::8fddcf911866fa713be3ba9323713f98 https://doi.org/10.1016/j.actamat.2014.03.013 Zobrazit plný text záznamu Full Text from ScienceDirect