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[REPM2025_P1-19_Urzhumtsev.pdf](https://mdr.nims.go.jp/filesets/3c1d1354-0a41-49a6-b175-da145e6ce23e/download)

## Creator

Andrey Urzhumtsev, Viktoria Maltseva, Alexey Volegov

## Rights

[Creative Commons BY Attribution 4.0 International](https://creativecommons.org/licenses/by/4.0/)

## Other metadata

[Features of the magnetization reversal processes in sintered permanent magnets Nd-Fe-B and Sm-Co type](https://mdr.nims.go.jp/datasets/001e18e8-c751-4d9f-a6a2-961544528914)

## Fulltext

POSTER_REPM AndreyFeatures of the magnetization reversal processes in sintered permanent magnets Nd-Fe-B and Sm-Co typeAndrey Urzhumtsev 1,2*, V. Maltseva 1, and A. Volegov 1  1 Ural Federal University, Institute of Natural Science and Mathematics, Yekaterinburg, Russia 2 POZ-Progress LLC., 624092, Verkhnyaya Pyshma, Russia  *e-mail: andrei.urzhumtsev@urfu.ru BACKGROUND The mechanism behind the high-coercivity state in sintered Nd-Fe-B and Sm(Co,Fe,Cu,Zr)_z permanent magnets remains unresolved. While traditionally attributed to nucleation (Nd₂Fe₁₄B) and domain wall pinning (Sm-based compounds), recent studies [1,2] indicate a more complex magnetisation reversal process.AIM To develop methods for determining the mechanisms of high-coercivity formation and to apply them to hard magnetic materials based on Nd-Fe-B and Sm(Co,Fe,Cu,Zr)_z compounds.APPROACHWe propose a method based on the analysis of magnetometric measurements, including:!"# !$# !%# # %# $# "##$#&#'#(#%##!)*+,-./0!)*1O+0!*!%0!*!$0!3*!%0!3*!$0!*!"0!3*!"0! " # $ % &!!&!"!'!#!(!$!! (!"#$%&!)*+,-.!(" ) # ! '(" )$*!.$'*!/!.(a) N35   (b) N48   (c) N48SHNd-Fe-B powder Sm-Co permanent magnets!"# !$B !$# !B # B $# $B "#!$##!B##B#$##10!"#$%&'!"&'(F*+,!-F!.!"#A!"AA!#AA#A"AA"#A!%A !&A !"A A "A &A!"#A!"AA!#AA#A"AA"#A!&A !"A A "A &A %A!'()*H,-.!10!!"#$% &!1 "!!"#$% &/%# /MN°'()*H,-.!'(O3)./MNQ5 S78!'(O3).!"# !$# # $# "#!%##!C##C#%##!'()*+,-.!'(/0).1*!O3!"## !$# !%# !C# !'# # '# C# %# $# "##!"(#!"##!(##(#"##"(#!"(#!"##!(##(#"##"(#! )*+,-./!0)1O*/!! "!#$%&'!!("!#$%&'3+!45S704,! )*+,-./3+!45%704,Nd-Fe-B permanent magnets• magnetization curves • differential susceptibility: dσ/dH • reversible susceptibility: χᵣ(H) • reversible contribution to magnetization: Δσ(H) = σ(H) – σᵣ(H)MQA (a) 6% Cu   (b) 9% Cu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grain boundary magnetization down magnetization up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ig.1. Magnetization and magnetization reversal  curvesFig.2. Magnetic ac reversable susceptibility χ(H) and χr(H = 0) and reversible contribution to magnetization Δσ(H)=σ(H)−σ r(H) P>>N N≈P N>>P P≈N P≈N P≈NP - pinning N - nucleationFig.3. Minor hysteresis loops from initial stateThis work was financially supported by FEUZ-2024-0060.[1] Urzhumtsev, A.N. et al. A Modified Kondorsky Model for Describing the Magnetization Reversal Processes in Nd–Fe–B Permanent Magnets[2] Urzhumtsev, A.N et. Al. Magnetization reversal processes in sintered permanent magnets Sm(Co, Fe, Zr, Cu)z‣ A method was developed to evaluate the roles of pinning and  nucleation in permanent magnets by analyzing the peak values of reversible magnetization Δσ(H) and reversible magnetic susceptibility χᵣ(H).  ‣ This method is especially effective for microcrystalline Nd-Fe-B magnets.‣ An anomalous decrease in magnetization with increasing field was observed in partial hysteresis loops for Nd-Fe-B magnets. ‣ This behavior indicates a predominance of single-domain grains with domain walls pinned at grain boundaries.‣ In Sm(Co,Fe,Zr,Cu)z magnets, an increase in magnetic susceptibility χ(H) under a demagnetizing field was observed. ‣ This may reflect the response of the Zr(Co,Cu)₃-type lamellar phase, previously strongly exchange-coupled with the 2:17 main phase.mailto:andrei.urzhumtsev@urfu.ru