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Title: Magnetization reversal in melt-quenched NdFeB

Abstract

Melt-quenched NdFeB is an important modern permanent magnet material. However, there still remains doubt as to the magnetization reversal mechanism which controls coercivity in material prepared by this processing route. To investigate this problem a new technique based on measurements of reversible magnetization along recoil curves has been used. The technique identifies the presence of free domain walls during magnetic reversal. For this study samples of isotropic (MQI), hot pressed (MQII) and die upset (MQIII) melt-quenched NdFeB were examined. The results indicate that in MQI free domain walls are not present during reversal and the reversal mechanism is most likely incoherent rotation of some form. Free domain walls are also not present during reversal in the majority of grains of MQII, even though initial magnetization measurements indicate that the grain size is large enough to support them. In MQIII free domain walls are present during reversal. These results are attributed to the reduced domain wall nucleation field in MQIII compared with MQII and the increased dipolar interactions in MQIII.

Authors:
Publication Date:
Research Org.:
Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE Office of Energy Research (ER) (US)
OSTI Identifier:
752925
Report Number(s):
BNL-66051; KC0202020
R&D Project: AS410MSD; TRN: AH200009%%25
DOE Contract Number:  
AC02-98CH10886
Resource Type:
Conference
Resource Relation:
Conference: Materials Research Society Spring Meeting, San Francisco, CA (US), 04/05/1999--04/09/1999; Other Information: PBD: 5 Apr 1999
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; NEODYMIUM ALLOYS; IRON ALLOYS; BORON ALLOYS; MAGNETIC MATERIALS; PERMANENT MAGNETS; FABRICATION; MAGNETIZATION; COERCIVE FORCE; DOMAIN STRUCTURE

Citation Formats

Crew, D C. Magnetization reversal in melt-quenched NdFeB. United States: N. p., 1999. Web. doi:10.2172/350917.
Crew, D C. Magnetization reversal in melt-quenched NdFeB. United States. https://doi.org/10.2172/350917
Crew, D C. 1999. "Magnetization reversal in melt-quenched NdFeB". United States. https://doi.org/10.2172/350917. https://www.osti.gov/servlets/purl/752925.
@article{osti_752925,
title = {Magnetization reversal in melt-quenched NdFeB},
author = {Crew, D C},
abstractNote = {Melt-quenched NdFeB is an important modern permanent magnet material. However, there still remains doubt as to the magnetization reversal mechanism which controls coercivity in material prepared by this processing route. To investigate this problem a new technique based on measurements of reversible magnetization along recoil curves has been used. The technique identifies the presence of free domain walls during magnetic reversal. For this study samples of isotropic (MQI), hot pressed (MQII) and die upset (MQIII) melt-quenched NdFeB were examined. The results indicate that in MQI free domain walls are not present during reversal and the reversal mechanism is most likely incoherent rotation of some form. Free domain walls are also not present during reversal in the majority of grains of MQII, even though initial magnetization measurements indicate that the grain size is large enough to support them. In MQIII free domain walls are present during reversal. These results are attributed to the reduced domain wall nucleation field in MQIII compared with MQII and the increased dipolar interactions in MQIII.},
doi = {10.2172/350917},
url = {https://www.osti.gov/biblio/752925}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Apr 05 00:00:00 EDT 1999},
month = {Mon Apr 05 00:00:00 EDT 1999}
}

Conference:
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