Micromagnetic simulation of the influence of grain boundary on cerium substituted Nd-Fe-B magnets

Liu, D.; Zhao, Tongyun; Li, R.; Zhang, M.; Shang, R. X.; Xiong, Jin; Zhang, J.; Sun, J. R.; Shen, Baogen

doi:10.1063/1.4972803

Cited by 29 publications

(12 citation statements)

References 19 publications

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“…With the variation of Ce, La and La-Ce substitution content, an abnormal increase of coercivity has been observed 9 , 11 , 13 , 16 . This phenomenon is more likely due to the variation in microstructure such as grain boundary instead of main phase, which is also supported by the micromagnetic simulation 17 . So it seems to be a feasible way to achieve the high-performance by partial substitution with a wide range of Ce.…”

Section: Introductionsupporting

confidence: 65%

“…The formation of boundary phase between adjacent grains has been observed from the TEM image. The boundary phase has been expected to cause a reduction in intergranular exchange coupling, which plays an important role in improving the coercivity 17 , 30 . The reduced intergranular exchange coupling is examined by the observation of magnetic domain structure with MFM (Fig.…”

Section: Discussionmentioning

confidence: 99%

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Magnetic hardening of Nd-Ce-Fe-B films with high Ce concentration

Ren

Abbas

Liu

et al. 2018

Sci Rep

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Partial substitution of Ce in Nd-Fe-B magnets is a feasible way to cope with the crisis of Nd and Dy in Nd-Fe-B production and reduce the cost of Nd-Fe-B magnets. In the present paper, the Nd-Ce-Fe-B films with high performance have been successfully fabricated by using an ultra-high vacuum (UHV) magnetron sputtering system. High magnetic performance with a ceorcivity of 13.3 kOe, a remanence of 11.4 kGs and a maximum energy product of 29.4 GMOe is obtained with the Ce substitution for more than 50 wt.% Nd without Dy addition. The high coercivity and (BH)max achieved in this work are much larger than those of previously reported Nd-Ce-Fe-B magnets with the same Ce concentration. The phase structure, microstructure and coercivity mechanism are analyzed. The coercivity mechanism is determined to be mainly dominated by nucleation. Based on the microstructure observation and coercivity mechanism analysis, the fine and well separated grains, smooth grain surface, small and less inhomogeneities should be responsible for the high coercivity. Our results encourage the further improvement of magnetic properties in Ce magnets including the bulk material with high Ce concentration.

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Section: Introductionsupporting

confidence: 65%

Section: Discussionmentioning

confidence: 99%

Magnetic hardening of Nd-Ce-Fe-B films with high Ce concentration

Ren

Abbas

Liu

et al. 2018

Sci Rep

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“…The maximum energy product (BH) max at RT was calculated using the density of 7.67 g cm −3 and a demagnetization correction (N ≈ 0.977). , respectively [24].…”

Section: Materials Characterizationsmentioning

confidence: 99%

A novel strategy for the fabrication of high-performance nanostructured Ce-Fe-B magnetic materials via electron-beam exposure

et al. 2021

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Ce 2 Fe 14 B compound has a great potential to serve as a novel permanent magnet alternative thanks to the abundant and inexpensive rare-earth element (cerium), while its low magnetocrystalline anisotropy and energy product severely restrict its applications. In this work, a novel strategy combining melt-spinning and electron-beam exposure (EBE) aiming for fabricating high-performance Ce-Fe-B magnetic materials is reported to solve the above-mentioned problem. Remarkably, this strategy facilitates developing a suitable grain boundary configuration without using any additional heavy rare-earth element. Under the optimal EBE condition, the maximum energy product ((BH) max ) of pure Ce-Fe-B alloy is 6.5 MGOe, about four times higher than that obtained after conventional rapid thermal processing method for the same precursor. The enhanced intergranular magnetostatic coupling effect in the EBE sample is validated by mapping the first-order-reversal-curve (FORC) diagrams. The in-situ observation of magnetic domain wall motion for Ce-Fe-B alloy using Lorentz transmission electron microscopy reveals that the boundary layers are very effective in pinning the motion of domain walls, leading to the increased coercivity under EBE, and this pinning effect is further verified by micromagnetic simulations. Our results suggest that CeFeB materials using EBE could be a promising candidate after further processing, which could fill the performance "gap" between hexaferrite and Nd-Fe-B-based magnets.

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“…The extrinsic magnetic properties are intimately related to the microstructure and its resultant complex magnetic interactions. The correlation between microstructure and magnetic properties can be revealed by micromagnetic simulation, which has been applied in R-Fe-B magnets [10,24,28]. To gain more insight on the effect of Nd/Pr distribution on coercivity, we perform micromagnetic simulation for several model microstructures.…”

Section: B Micromagnetic Simulation On Ce-nd-fe-b Magnetmentioning

confidence: 99%

“…However, their growing demands continue to strain the supply of the rare earth elements (R) used in the magnet including Nd, Pr, Dy and Tb. Thus, resource-rich and cost-effective Ce2Fe14B (2:14:1) based permanent magnets have been intensively investigated in recent years [3][4][5][6][7][8][9][10]. However, the intrinsic magnetic properties including spontaneous magnetization (Js), magnetic anisotropy field (Ha) and Curie temperature (Tc) of Ce2Fe14B are far inferior to those of Nd2Fe14B.…”

Section: Introductionmentioning

confidence: 99%

Theoretical Correlation of Elemental Distribution of Nd and Pr in Ce-Fe-B Microstructure With Hard Magnetic Properties

2021

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Relatively resource rich-, but property inferior-Ce-Fe-B magnet can be improved by partial replacement of Ce by Nd and/or Pr. In addition to the amount of Nd/Pr, their distribution profile in microstructure plays important role. From our first principles DFT (density functional theory) calculation, the substitution energy of Ce by Pr/Nd is negative in Ce2Fe14B (2:14:1) while that for laves phase CeFe2 is positive, implying that Nd/Pr stabilize 2:14:1 and suppress formation of the CeFe2 phase. Micromagnetic simulation indicates that homogenized distribution of Nd/Pr improves squareness of demagnetization curve while core (Ce-rich)-shell (Nd/Prrich) 2:14:1 grain structure enhances coercivity. Magnetic properties of Ce-Fe-B can be optimized by manipulating distribution profile of chemical element in microstructure based on their subtle difference in thermodynamic property, which is an effective pathway to design optimized chemical composition and processing route for high performance magnet.

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Micromagnetic simulation of the influence of grain boundary on cerium substituted Nd-Fe-B magnets

Cited by 29 publications

References 19 publications

Magnetic hardening of Nd-Ce-Fe-B films with high Ce concentration

Magnetic hardening of Nd-Ce-Fe-B films with high Ce concentration

A novel strategy for the fabrication of high-performance nanostructured Ce-Fe-B magnetic materials via electron-beam exposure

Theoretical Correlation of Elemental Distribution of Nd and Pr in Ce-Fe-B Microstructure With Hard Magnetic Properties

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