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A Self-Assembly of Single Layer of Co Nanorods to Reveal the Magnetostatic Interaction Mechanism. NANOMATERIALS 2022; 12:nano12142499. [PMID: 35889723 PMCID: PMC9318953 DOI: 10.3390/nano12142499] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 07/12/2022] [Accepted: 07/19/2022] [Indexed: 12/26/2022]
Abstract
In this work, we report a self-assembly method to fabricate a single layer of Co nanorods to study their magnetostatic interaction behavior. The Co nanorods with cambered and flat tips were synthesized by using a solvothermal route and an alcohol–thermal method, respectively. Both of them represent hard magnetic features. Co nanorods with cambered tips have an average diameter of 10 nm and length of 100 nm with coercivity of 6.4 kOe, and flat-tip nanorods with a 30 nm diameter and 100 nm length exhibit a coercivity of 4.9 kOe. They are further assembled on the surface of water in assistance of surfactants. The results demonstrate that the assembly type is dependent on the magnetic induction lines direction. For Co nanorods with flat tips, most of magnetic induction lines are parallel to the length direction, leading to an assembly that is tip to tip. For Co nanorods with cambered tips, they are prone to holding together side by side for their random magnetic induction lines. Under an applied field, the Co nanorods with flat tips can be further aligned into a single layer of Co nanorods. Our work gives a possible mechanism for the magnetic interaction of Co nanorods and provides a method to study their magnetic behavior.
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Yang Z, Chen Y, Liu W, Wang Y, Li Y, Zhang D, Lu Q, Wu Q, Zhang H, Yue M. Effects of Shape Anisotropy on Hard–Soft Exchange-Coupled Permanent Magnets. NANOMATERIALS 2022; 12:nano12081261. [PMID: 35457969 PMCID: PMC9031079 DOI: 10.3390/nano12081261] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 04/01/2022] [Accepted: 04/06/2022] [Indexed: 12/13/2022]
Abstract
Exchange-coupled magnets are promising candidates for a new generation of permanent magnets. Here, we investigated the effect of soft magnetic shell thickness and the aspect ratio of the hard magnetic core on the magnetic properties for isolated core/shell cylinder exchange-coupled magnets, as well as the packing effect of the cylindrical array via a micromagnetic simulation method. It was found that the shape anisotropy contributions to the magnetic properties in the cylindrical core/shell exchange-coupled magnets are closely related to the thickness of the soft magnetic shell. When the soft magnetic shell is thin, the magnetic properties are dominated by the hard–soft exchange coupling effects, and the contributions of shape anisotropy are quite limited. When the soft magnetic shell is relatively thick, utilizing shape anisotropy would be an effective method to improve the magnetic performance of hard–soft exchange-coupled magnets. The present work provides an in-depth fundamental understanding of the underlying magnetization reversal mechanism. This work could be useful for designing high-performance permanent magnets and avoiding pitfalls.
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Zheng B, Fan J, Chen B, Qin X, Wang J, Wang F, Deng R, Liu X. Rare-Earth Doping in Nanostructured Inorganic Materials. Chem Rev 2022; 122:5519-5603. [PMID: 34989556 DOI: 10.1021/acs.chemrev.1c00644] [Citation(s) in RCA: 169] [Impact Index Per Article: 84.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Impurity doping is a promising method to impart new properties to various materials. Due to their unique optical, magnetic, and electrical properties, rare-earth ions have been extensively explored as active dopants in inorganic crystal lattices since the 18th century. Rare-earth doping can alter the crystallographic phase, morphology, and size, leading to tunable optical responses of doped nanomaterials. Moreover, rare-earth doping can control the ultimate electronic and catalytic performance of doped nanomaterials in a tunable and scalable manner, enabling significant improvements in energy harvesting and conversion. A better understanding of the critical role of rare-earth doping is a prerequisite for the development of an extensive repertoire of functional nanomaterials for practical applications. In this review, we highlight recent advances in rare-earth doping in inorganic nanomaterials and the associated applications in many fields. This review covers the key criteria for rare-earth doping, including basic electronic structures, lattice environments, and doping strategies, as well as fundamental design principles that enhance the electrical, optical, catalytic, and magnetic properties of the material. We also discuss future research directions and challenges in controlling rare-earth doping for new applications.
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Affiliation(s)
- Bingzhu Zheng
- State Key Laboratory of Silicon Materials, Institute for Composites Science Innovation, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Jingyue Fan
- Department of Chemistry, National University of Singapore, Singapore 117543, Singapore
| | - Bing Chen
- Department of Materials Science and Engineering, City University of Hong Kong, Hong Kong SAR 999077, China
| | - Xian Qin
- Department of Chemistry, National University of Singapore, Singapore 117543, Singapore
| | - Juan Wang
- Institute of Environmental Health, MOE Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental & Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Feng Wang
- Department of Materials Science and Engineering, City University of Hong Kong, Hong Kong SAR 999077, China
| | - Renren Deng
- State Key Laboratory of Silicon Materials, Institute for Composites Science Innovation, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Xiaogang Liu
- Department of Chemistry, National University of Singapore, Singapore 117543, Singapore
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Wu Q, Ma X, Yue M, Cong L, Ma Z, Zhang D, Li Y, Wang Y. Tip Interface Exchange-Coupling Based on "Bi-Anisotropic" Nanocomposites with Low Rare-Earth Content. ACS APPLIED MATERIALS & INTERFACES 2021; 13:13548-13555. [PMID: 33703872 DOI: 10.1021/acsami.0c21669] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Specially designed SmCo5/Co magnetic nanocomposites have been fabricated by a "bottom up" process. SmCo5 nanochips were first prepared by solution-phase chemical synthesis combined with reductive annealing and then coated by chemical deposition of Co nanorods. Both the SmCo5 nanochips and Co nanorods are anisotropic and could be simultaneously aligned under the external magnetic field. Magnetic measurements applied on these "bi-anisotropic" SmCo5/Co composites show high magnetic performance with the Co phase content in a wide range from 10 to 80 wt %. For the first time ever, the applicable exchange-coupled nanocomposites with a rare-earth content lower than 7 wt % was realized, which exhibits the coercivity close to 10 kOe and remanence 31% larger than that of single phase SmCo5. 3-D micromagnetic simulations were performed to reveal that the reversal mechanism in the Co phase was transferred from the incoherent mode to the coherent mode under a tip interface exchange-coupling with a SmCo5 surface.
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Affiliation(s)
- Qiong Wu
- College of Materials Science and Engineering, Key Laboratory of Advanced Functional Materials, Ministry of Education of China, Beijing University of Technology, Beijing 100124, China
| | - Xiangyu Ma
- College of Materials Science and Engineering, Key Laboratory of Advanced Functional Materials, Ministry of Education of China, Beijing University of Technology, Beijing 100124, China
| | - Ming Yue
- College of Materials Science and Engineering, Key Laboratory of Advanced Functional Materials, Ministry of Education of China, Beijing University of Technology, Beijing 100124, China
| | - Liying Cong
- College of Materials Science and Engineering, Key Laboratory of Advanced Functional Materials, Ministry of Education of China, Beijing University of Technology, Beijing 100124, China
| | - Zhenhui Ma
- College of Materials Science and Engineering, Key Laboratory of Advanced Functional Materials, Ministry of Education of China, Beijing University of Technology, Beijing 100124, China
| | - Dongtao Zhang
- College of Materials Science and Engineering, Key Laboratory of Advanced Functional Materials, Ministry of Education of China, Beijing University of Technology, Beijing 100124, China
| | - Yuqing Li
- College of Materials Science and Engineering, Key Laboratory of Advanced Functional Materials, Ministry of Education of China, Beijing University of Technology, Beijing 100124, China
| | - Yatao Wang
- College of Materials Science and Engineering, Key Laboratory of Advanced Functional Materials, Ministry of Education of China, Beijing University of Technology, Beijing 100124, China
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Trinh TT, Kim J, Sato R, Matsumoto K, Teranishi T. Synthesis of mesoscopic particles of multi-component rare earth permanent magnet compounds. SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 2021; 22:37-54. [PMID: 33536840 PMCID: PMC7833049 DOI: 10.1080/14686996.2020.1862630] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 12/06/2020] [Accepted: 12/07/2020] [Indexed: 05/08/2023]
Abstract
Multielement rare earth (R)-transition metal (T) intermetallics are arguably the next generation of high-performance permanent magnetic materials for future applications in energy-saving and renewable energy technologies. Pseudobinary Sm2Fe17N3 and (R,Zr)(Fe,Co,Ti)12 (R = Nd, Sm) compounds have the highest potential to meet current demands for rare-earth-element-lean permanent magnets (PMs) with ultra-large energy product and operating temperatures up to 200°C. However, the synthesis of these materials, especially in the mesoscopic scale for maximizing the maximum energy product (B H m a x ), remains a great challenge. Nonequilibrium processes are apparently used to overcome the phase-stabilization challenge in preparing the R-T intermetallics but have limited control of the material's microstructure. More radical bottom-up nanoparticle approaches based on chemical synthesis have also been explored, owing to their potential to achieve the desired composition, structure, size, and shape. While a great achievement has been made for the Sm2Fe17N3, progress in the synthesis of (R,Zr)(Fe,Co,Ti)12 magnetic mesoscopic particles (MMPs) and R-T/T exchange-coupled nanocomposites (NCMs) with substantial coercivity (H c ) and remanence (M r ) , respectively, remains marginal.
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Affiliation(s)
- T. Thuy Trinh
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, Japan
| | - Jungryang Kim
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, Japan
| | - Ryota Sato
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, Japan
| | - Kenshi Matsumoto
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, Japan
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