Structural Design of High-Coercivity Nd-Ce-Fe-B Magnets with Easy Axis Perpendicular Orientation and High-Abundance Ce Content Based on Micromagnetic Simulations.
Saved in:
| Title: | Structural Design of High-Coercivity Nd-Ce-Fe-B Magnets with Easy Axis Perpendicular Orientation and High-Abundance Ce Content Based on Micromagnetic Simulations. |
|---|---|
| Authors: | Zhao, Qian1 (AUTHOR) zhaoqianqm@163.com, Yu, Ying1,2 (AUTHOR), Tang, Chenlin1,3 (AUTHOR), Hu, Qingkang1,4 (AUTHOR), Bai, Suo1 (AUTHOR), Wang, Puyu2 (AUTHOR), Li, Zhubai3 (AUTHOR), Zhao, Guoping4 (AUTHOR) |
| Source: | Nanomaterials (2079-4991). Sep2025, Vol. 15 Issue 17, p1358. 20p. |
| Subjects: | Coercive fields (Electronics), Micromagnetics, Magnetic flux density, Demagnetization, Permanent magnets |
| Abstract: | In recent years, replacing the scarce and expensive rare earth element Nd with the more abundant and lower cost Ce in the production of Nd-Ce-Fe-B permanent magnets has become a focus of both industrial and academic research. A critical challenge is how to design the crystal structure of Nd-Ce-Fe-B magnets to compensate for the decline in magnetic performance caused by the Ce substitution. In this study, based on micromagnetic theory, Nd-Ce-Fe-B magnets with perpendicularly oriented easy axes—in which the two main phases, Nd2Fe14B and Ce2Fe14B, have a volume ratio of 1:1 but different spatial arrangements—are modeled and simulated using the MuMax3.11 software. The model is either cubic or spherical. The results from the demagnetization curve analysis indicate that the coercivity mechanism of all magnets is pinning. When the magnet volume is constant but the phase distribution differs, the Nd2Fe14B/Ce2Fe14B structure exhibits a higher coercivity and maximum energy product than the Ce2Fe14B/Nd2Fe14B structure. Furthermore, for both structural models with the same phase distribution, the coercivity and the maximum energy product decrease with the increasing volume of the main phase. Notably, the coercivity is similar when the magnet volume is very small and stabilizes after reaching a certain threshold. This qualitative conclusion was also observed in Nd-Dy-Fe-B magnets with the same structure and equal volume ratio of the two main phases. This general finding indicates that, in biphasic magnets with equal phase volumes, the phase with the larger anisotropy field located at the grain periphery can achieve a higher coercivity and maximum magnetic energy product. The analysis of the angular distribution reveals that the number of magnetic domains remains fixed at six in the Nd2Fe14B/Ce2Fe14B structure and two in the Ce2Fe14B/Nd2Fe14B structure. The in-plane magnetic moment analysis of the Ce2Fe14B/Nd2Fe14B magnet shows that the magnetic moments at the edges of the Ce2Fe14B begin to deflect first. Even at the pinning stage, the magnetic moments within the Nd2Fe14B remain unrotated. Nevertheless, the surface magnetic moments of Ce2Fe14B, through exchange coupling, drive the deflection of the interfacial and interior moments, completing the entire demagnetization process. These computational results provide theoretical guidance for related experimental studies and industrial applications. [ABSTRACT FROM AUTHOR] |
| Copyright of Nanomaterials (2079-4991) is the property of MDPI and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
|
Full text is not displayed to guests.
Login for full access.
|
|
| Abstract: | In recent years, replacing the scarce and expensive rare earth element Nd with the more abundant and lower cost Ce in the production of Nd-Ce-Fe-B permanent magnets has become a focus of both industrial and academic research. A critical challenge is how to design the crystal structure of Nd-Ce-Fe-B magnets to compensate for the decline in magnetic performance caused by the Ce substitution. In this study, based on micromagnetic theory, Nd-Ce-Fe-B magnets with perpendicularly oriented easy axes—in which the two main phases, Nd2Fe14B and Ce2Fe14B, have a volume ratio of 1:1 but different spatial arrangements—are modeled and simulated using the MuMax3.11 software. The model is either cubic or spherical. The results from the demagnetization curve analysis indicate that the coercivity mechanism of all magnets is pinning. When the magnet volume is constant but the phase distribution differs, the Nd2Fe14B/Ce2Fe14B structure exhibits a higher coercivity and maximum energy product than the Ce2Fe14B/Nd2Fe14B structure. Furthermore, for both structural models with the same phase distribution, the coercivity and the maximum energy product decrease with the increasing volume of the main phase. Notably, the coercivity is similar when the magnet volume is very small and stabilizes after reaching a certain threshold. This qualitative conclusion was also observed in Nd-Dy-Fe-B magnets with the same structure and equal volume ratio of the two main phases. This general finding indicates that, in biphasic magnets with equal phase volumes, the phase with the larger anisotropy field located at the grain periphery can achieve a higher coercivity and maximum magnetic energy product. The analysis of the angular distribution reveals that the number of magnetic domains remains fixed at six in the Nd2Fe14B/Ce2Fe14B structure and two in the Ce2Fe14B/Nd2Fe14B structure. The in-plane magnetic moment analysis of the Ce2Fe14B/Nd2Fe14B magnet shows that the magnetic moments at the edges of the Ce2Fe14B begin to deflect first. Even at the pinning stage, the magnetic moments within the Nd2Fe14B remain unrotated. Nevertheless, the surface magnetic moments of Ce2Fe14B, through exchange coupling, drive the deflection of the interfacial and interior moments, completing the entire demagnetization process. These computational results provide theoretical guidance for related experimental studies and industrial applications. [ABSTRACT FROM AUTHOR] |
|---|---|
| ISSN: | 20794991 |
| DOI: | 10.3390/nano15171358 |
