Abstract
Ce2Fe14B 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.

摘要
Ce2Fe14B作为一种基于广泛而廉价的稀土(铈)的新型永磁体, 低矫顽力和低最大磁能积严重限制了其在永磁领域中的应用. 在 这项工作中, 我们报道了一种将熔融纺丝技术和电子束曝光(EBE) 技术结合的新方法, 旨在制造高性能Ce-Fe-B磁体. 值得注意的是, 该方法可以在不使用任何其他重稀土元素的情况下调控出合适的 晶界构型. 在最佳EBE条件下, 纯Ce-Fe-B合金的最大磁能积为 6.5 MGOe, 比常规快速热处理方法制备的合金的最大磁能积高四 倍左右. 这说明, 使用EBE制备的CeFeB材料作为前驱体, 经过进一 步加工之后, 如热变形或烧结, 有望填补六角铁氧体与Nd-Fe-B磁 体之间的市场空白.
References
Gutfleisch O, Willard MA, Brück E, et al. Magnetic materials and devices for the 21st century: Stronger, lighter, and more energy efficient. Adv Mater, 2011, 23: 821–842
Schrefl T, Fidler J, Kronmüller H. Remanence and coercivity in isotropic nanocrystalline permanent magnets. Phys Rev B, 1994, 49: 6100–6110
Manaf A, Buckley RA, Davies HA, et al. Enhanced magnetic properties in rapidly solidified Nd-Fe-B based alloys. J Magn Magn Mater, 1991, 101: 360–362
Ramesh R, Thomas G, Ma BM. Magnetization reversal in nucleation controlled magnets. II. Effect of grain size and size distribution on intrinsic coercivity of Fe-Nd-B magnets. J Appl Phys, 1988, 64: 6416–6423
Lee RW. Hot-pressed neodymium-iron-boron magnets. Appl Phys Lett, 1985, 46: 790–791
Pathak AK, Khan M, Gschneidner Jr. KA, et al. Cerium: An unlikely replacement of dysprosium in high performance Nd-Fe-B permanent magnets. Adv Mater, 2015, 27: 2663–2667
Zha L, Han Y, Pi L, et al. Growth of quasi-texture in nanostructured magnets with ultra-high coercivity. Acta Mater, 2020, 195: 282–291
Hono K, Sepehri-Amin H. Strategy for high-coercivity Nd-Fe-B magnets. Scripta Mater, 2012, 67: 530–535
Kronmüller H, Schrefl T. Interactive and cooperative magnetization processes in hard magnetic materials. J Magn Magn Mater, 1994, 129: 66–78
Fidler J, Bernardi J. Transmission electron microscope characterization of cast and hot-worked R-Fe-B:Cu (R = Nd, Pr) permanent magnets. J Appl Phys, 1991, 70: 6456–6458
Vial F, Joly F, Nevalainen E, et al. Improvement of coercivity of sintered NdFeB permanent magnets by heat treatment. J Magn Magn Mater, 2002, 242–245: 1329–1334
Sawatzki S, Kübel C, Ener S, et al. Grain boundary diffusion in nanocrystalline Nd-Fe-B permanent magnets with low-melting eutectics. Acta Mater, 2016, 115: 354–363
Kim TH, Sasaki TT, Ohkubo T, et al. Microstructure and coercivity of grain boundary diffusion processed dy-free and dy-containing Nd-Fe-B sintered magnets. Acta Mater, 2019, 172: 139–149
Ma T, Yan M, Wu K, et al. Grain boundary restructuring of multi-main-phase Nd-Ce-Fe-B sintered magnets with Nd hydrides. Acta Mater, 2018, 142: 18–28
Herbst JF, Meyer MS, Pinkerton FE. Magnetic hardening of Ce2Fe14B. J Appl Phys, 2012, 111: 07A718
Zhang ZY, Zhao LZ, Zhong XC, et al. Phase precipitation behavior of melt-spun ternary Ce2Fe14B alloy during rapid quenching and heat treatment. J Magn Magn Mater, 2017, 441: 429–435
Jin ZQ, Liu JP. Rapid thermal processing of magnetic materials. J Phys D-Appl Phys, 2006, 39: R227–R244
Zhang Y, Ma T, Jin J, et al. Effects of REFe2 on microstructure and magnetic properties of Nd-Ce-Fe-B sintered magnets. Acta Mater, 2017, 128: 22–30
Zhang JS, Zhao LZ, Liao XF, et al. Suppressing the CeFe2 phase formation and improving the coercivity and thermal stability of Ce-Fe-B alloys by Si substitution. Intermetallics, 2019, 107: 75–80
Zha L, Wu R, Liu Z, et al. Efficiently controlling crystallization and magnetic properties of nanostructured Nd-Ce-Fe-B ribbons via electron beam exposure. J Alloys Compd, 2019, 807: 151669
Yang J, Han J, Tian H, et al. Structural and magnetic properties of nanocomposite Nd-Fe-B prepared by rapid thermal processing. Engineering, 2020, 6: 132–140
Cheisson T, Schelter EJ. Rare earth elements: Mendeleev’s bane, modern marvels. Science, 2019, 363: 489–493
Massari S, Ruberti M. Rare earth elements as critical raw materials: Focus on international markets and future strategies. Resources Policy, 2013, 38: 36–43
Liu D, Zhao TY, Li R, et al. Micromagnetic simulation of the influence of grain boundary on cerium substituted Nd-Fe-B magnets. AIP Adv, 2017, 7: 056201
Chu KT, Jin ZQ, Chakka VM, et al. Rapid magnetic hardening by rapid thermal annealing in NdFeB-based nanocomposites. J Phys D-Appl Phys, 2006, 39: 429
Tian H, Zhang Y, Han J, et al. Synergetic crystallization in a Nd2Fe14B/α-Fe nanocomposite under electron beam exposure conditions. Nanoscale, 2016, 8: 18221–18227
Dalmas de Reotier P, Fruchart D, Pontonnier L, et al. Structural and magnetic properties of RE2Fe14BH(D)x; RE=Y, Ce, Er. J Less Common Met, 1987, 129: 133–144
Wang T, Medraj M. Intrinsic magnetic properties of Ce2(Fe, Co)14B and its modifications by Ni and Cu. J Alloys Compd, 2018, 763: 916–925
Skoug EJ, Meyer MS, Pinkerton FE, et al. Crystal structure and magnetic properties of Ce2Fe14−xCoxB alloys. J Alloys Compd, 2013, 574: 552–555
Hirota K, Nakamura H, Minowa T, et al. Coercivity enhancement by the grain boundary diffusion process to Nd-Fe-B sintered magnets. IEEE Trans Magn, 2006, 42: 2909–2911
Akiya T, Liu J, Sepehri-Amin H, et al. High-coercivity hot-deformed Nd-Fe-B permanent magnets processed by Nd-Cu eutectic diffusion under expansion constraint. Scripta Mater, 2014, 81: 48–51
Sasaki TT, Takada Y, Okazaki H, et al. Role of Ga on the high coercivity of Nd-rich Ga-doped Nd-Fe-B sintered magnet. J Alloys Compd, 2019, 790: 750–759
Zhang L, Zhu M, Song L, et al. The technology and mechanism of coercivity promotion of Ce-rich dual-main-phase sintered magnets. J Magn Magn Mater, 2019, 490: 165414
Wang Z, Zhang J, Wang J, et al. Coercivity improvement of hot-deformed Nd-Fe-B magnets by stress-induced Pr-Cu eutectic diffusion. Acta Mater, 2018, 156: 136–145
Soderžnik M, Sepehri-Amin H, Sasaki TT, et al. Magnetization reversal of exchange-coupled and exchange-decoupled Nd-Fe-B magnets observed by magneto-optical Kerr effect microscopy. Acta Mater, 2017, 135: 68–76
Hu H, Peng CJ, Krupanidhi SB. Effect of heating rate on the crystallization behavior of amorphous PZT thin films. Thin Solid Films, 1993, 223: 327–333
Serin B, Ellickson RT. Determination of diffusion coefficients. J Chem Phys, 1941, 9: 742–747
Allnatt AR, Chadwick AV. Thermal diffusion in crystalline solids. Chem Rev, 1967, 67: 681–705
Harrison RJ, Feinberg JM. FORCinel: An improved algorithm for calculating first-order reversal curve distributions using locally weighted regression smoothing. Geochem Geophys Geosyst, 2008, 9: Q05016
Roberts AP, Pike CR, Verosub KL. First-order reversal curve diagrams: A new tool for characterizing the magnetic properties of natural samples. J Geophys Res, 2000, 105: 28461–28475
Pike CR, Roberts AP, Verosub KL. Characterizing interactions in fine magnetic particle systems using first order reversal curves. J Appl Phys, 1999, 85: 6660–6667
Zhu X, Tang X, Pei K, et al. Direct observation of magnetization reversal of hot-deformed Nd-Fe-B magnet. AIP Adv, 2018, 8: 015227
Acknowledgements
This work was supported by the National Key Research and Development Program of China (2016YFB0700901), the National Natural Science Foundation of China (51731001, 11675006 and 51371009). We appreciate the financial support from the China Scholarship Council (CSC) by a State Scholarship Fund (201906010220). The authors thank Dr. Yanli Li at the Institute of Electrical Engineering (Chinese Academy of Sciences, Beijing, China) for experimental guidance, M.S. Meiling Zhang at the Central Iron & Steel Research Institute (Beijing, China) for aiding in the TEM characterizations, M.S. Jin Zhu for TEM sample preparing. Alberto Bollero acknowledges support from the “Severo Ochoa” Programme for Centres of Excellence in R&D (MINECO, SEV-2016-0686).
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Zha L designed and performed the experiments, and wrote the paper; Kim C completed the micromagnetic simulation; Xia W and Yang J supervised this study. All authors contributed to the general discussion and revision of the manuscript.
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The authors declare that they have no conflict of interest.
Liang Zha received his Bachelor’s degree from Anhui University in 2016. Currently, he is a PhD candidate at Peking University (PKU). His current research interest focuses on the synthesis and design of functional magnetic materials.
Jinbo Yang is a professor and the leader of the Center for Magnetism Magnetics at the School of Physics, PKU. He received his PhD in condensed matter physics from PKU in 1998 and performed post-doctoral research at the Leibniz Institute for Solid State and Materials Research-Dresden Germany from 1998 to 2000. He then worked at the University of Missouri-Rolla (UMR) from 2001 to 2008. He became a full professor at PKU in 2008. His research interest focuses on the structure and magnetism in condensed matter, including hard/soft magnets, crystal, magnetic and electronic structures of magnetic materials, nanomagnetism and spintronics.
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A novel strategy for the fabrication of high-performance nanostructured Ce-Fe-B magnetic materials via electron-beam exposure
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Zha, L., Kim, C., Yun, C. et al. A novel strategy for the fabrication of high-performance nanostructured Ce-Fe-B magnetic materials via electron-beam exposure. Sci. China Mater. 64, 2519–2529 (2021). https://doi.org/10.1007/s40843-020-1650-2
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DOI: https://doi.org/10.1007/s40843-020-1650-2
Keywords
- nanoscale magnets
- rapid thermal annealing
- Ce-Fe-B
- magnetic properties
- nanocrystalline material