Revealing the mystery of the cases where Nd–Fe–B magnetic like poles attract each other

Abstract This investigation reveals the mystery of the cases where magnetic like poles attract each other, and unlike poles repel one another. It is identified that for two unequally sized like poles, the pole with a higher P c (permeance coefficient) causes a localized demagnetization (LD) to the p...

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Autores principales:	Hui Meng, Guiping Tang, Abby Shen, Michelle Qian, Qifeng Wei, George Mizzell, Christina H. Chen
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2021
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/374798c5efba4b7ba0569dee45ca34fa
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spelling	oai:doaj.org-article:374798c5efba4b7ba0569dee45ca34fa2021-12-02T17:41:27ZRevealing the mystery of the cases where Nd–Fe–B magnetic like poles attract each other10.1038/s41598-021-91969-82045-2322https://doaj.org/article/374798c5efba4b7ba0569dee45ca34fa2021-06-01T00:00:00Zhttps://doi.org/10.1038/s41598-021-91969-8https://doaj.org/toc/2045-2322Abstract This investigation reveals the mystery of the cases where magnetic like poles attract each other, and unlike poles repel one another. It is identified that for two unequally sized like poles, the pole with a higher P c (permeance coefficient) causes a localized demagnetization (LD) to the pole with a lower P c . If the LD is large enough, the polarity of a localized area can be reversed, resulting in an attraction between these two like poles in the LD area in a small gap. Two unusual behaviors are observed: (1) an inflection point IP appears on the force vs gap curves of all the unequally sized like poles since they have different P c . Normally, the like poles’ repelling force increases when the gap decreases, but this IP results in nonmonotonic curves, even an attractive force in a small gap; (2) for some NdFeB magnets with a low coercivity and nonlinear B–H curve in the 2nd quadrant, a repulsion can occur for these unequal sized unlike poles, after previously pairing with their like poles that left an unrecoverable LD and reversed polarity area. The relationship of the LD, the P c ratio, and the B–H curve are also explored in this paper.Hui MengGuiping TangAbby ShenMichelle QianQifeng WeiGeorge MizzellChristina H. ChenNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 11, Iss 1, Pp 1-10 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Hui Meng Guiping Tang Abby Shen Michelle Qian Qifeng Wei George Mizzell Christina H. Chen Revealing the mystery of the cases where Nd–Fe–B magnetic like poles attract each other
description	Abstract This investigation reveals the mystery of the cases where magnetic like poles attract each other, and unlike poles repel one another. It is identified that for two unequally sized like poles, the pole with a higher P c (permeance coefficient) causes a localized demagnetization (LD) to the pole with a lower P c . If the LD is large enough, the polarity of a localized area can be reversed, resulting in an attraction between these two like poles in the LD area in a small gap. Two unusual behaviors are observed: (1) an inflection point IP appears on the force vs gap curves of all the unequally sized like poles since they have different P c . Normally, the like poles’ repelling force increases when the gap decreases, but this IP results in nonmonotonic curves, even an attractive force in a small gap; (2) for some NdFeB magnets with a low coercivity and nonlinear B–H curve in the 2nd quadrant, a repulsion can occur for these unequal sized unlike poles, after previously pairing with their like poles that left an unrecoverable LD and reversed polarity area. The relationship of the LD, the P c ratio, and the B–H curve are also explored in this paper.
format	article
author	Hui Meng Guiping Tang Abby Shen Michelle Qian Qifeng Wei George Mizzell Christina H. Chen
author_facet	Hui Meng Guiping Tang Abby Shen Michelle Qian Qifeng Wei George Mizzell Christina H. Chen
author_sort	Hui Meng
title	Revealing the mystery of the cases where Nd–Fe–B magnetic like poles attract each other
title_short	Revealing the mystery of the cases where Nd–Fe–B magnetic like poles attract each other
title_full	Revealing the mystery of the cases where Nd–Fe–B magnetic like poles attract each other
title_fullStr	Revealing the mystery of the cases where Nd–Fe–B magnetic like poles attract each other
title_full_unstemmed	Revealing the mystery of the cases where Nd–Fe–B magnetic like poles attract each other
title_sort	revealing the mystery of the cases where nd–fe–b magnetic like poles attract each other
publisher	Nature Portfolio
publishDate	2021
url	https://doaj.org/article/374798c5efba4b7ba0569dee45ca34fa
work_keys_str_mv	AT huimeng revealingthemysteryofthecaseswherendfebmagneticlikepolesattracteachother AT guipingtang revealingthemysteryofthecaseswherendfebmagneticlikepolesattracteachother AT abbyshen revealingthemysteryofthecaseswherendfebmagneticlikepolesattracteachother AT michelleqian revealingthemysteryofthecaseswherendfebmagneticlikepolesattracteachother AT qifengwei revealingthemysteryofthecaseswherendfebmagneticlikepolesattracteachother AT georgemizzell revealingthemysteryofthecaseswherendfebmagneticlikepolesattracteachother AT christinahchen revealingthemysteryofthecaseswherendfebmagneticlikepolesattracteachother
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Revealing the mystery of the cases where Nd–Fe–B magnetic like poles attract each other

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