Yang-Ki Hong;Seok Bae;Jihoon Park;Minyeong Choi;Won-Cheol Lee;Chang-Dong Yeo;Md Abdul Wahed;Kisuk Lee;Haein Yim-Choi;Woo-Young Lee
{"title":"无稀土磁体的分析最大能积(BH)max模型:核-壳纳米结构","authors":"Yang-Ki Hong;Seok Bae;Jihoon Park;Minyeong Choi;Won-Cheol Lee;Chang-Dong Yeo;Md Abdul Wahed;Kisuk Lee;Haein Yim-Choi;Woo-Young Lee","doi":"10.1109/TMAG.2025.3576933","DOIUrl":null,"url":null,"abstract":"This article presents an analytical model for the maximum energy product [<inline-formula> <tex-math>$(BH)_{\\max }$ </tex-math></inline-formula>] in core–shell structured magnetic exchange-coupled nanomagnets. The model was validated by comparing its results to the <inline-formula> <tex-math>$(BH)_{\\max }$ </tex-math></inline-formula> from core–shell magnets reported in the literature. This approach can serve as a universal model for designing core–shell magnets that achieve the desired <inline-formula> <tex-math>$(BH)_{\\max }$ </tex-math></inline-formula>. The <inline-formula> <tex-math>$(BH)_{\\max }$ </tex-math></inline-formula> was determined under two distinct nucleation field (<inline-formula> <tex-math>$H_{\\mathrm {N}}$ </tex-math></inline-formula>) conditions: <inline-formula> <tex-math>$H_{\\mathrm {N}} \\le M_{\\mathrm {r}}$ </tex-math></inline-formula>/2 and <inline-formula> <tex-math>$H_{\\mathrm {N}} \\ge M_{\\mathrm {r}}$ </tex-math></inline-formula>/2, where <inline-formula> <tex-math>$M_{\\mathrm {r}}$ </tex-math></inline-formula> is the remanent magnetization. In addition, two different values of magnetic hysteresis loop squareness (SQ <inline-formula> <tex-math>$= M_{\\mathrm {r}}$ </tex-math></inline-formula>/<inline-formula> <tex-math>$M_{\\mathrm {S}}$ </tex-math></inline-formula>) were used: 1.0 and 0.7. The soft magnetic shell’s remanent magnetic flux density (<inline-formula> <tex-math>$B_{\\mathrm {r}}$ </tex-math></inline-formula>) ranged from 0.7 to 2.2 T, while the core diameter (<inline-formula> <tex-math>$D_{\\mathrm {h}}$ </tex-math></inline-formula>) varied between 50 and 250 nm in this <inline-formula> <tex-math>$(BH)_{\\max }$ </tex-math></inline-formula> model. The low-temperature phase (LTP) MnBi-core/soft-shell nanomagnet can achieve a <inline-formula> <tex-math>$(BH)_{\\max }$ </tex-math></inline-formula> of 40 MGOe at a <inline-formula> <tex-math>$B_{\\mathrm {r}}$ </tex-math></inline-formula> of 1.6 T, with a shell thickness (<inline-formula> <tex-math>$\\delta _{\\mathrm {S}}$ </tex-math></inline-formula>) of 40 nm, a <inline-formula> <tex-math>$D_{\\mathrm {h}}$ </tex-math></inline-formula> of 250 nm, and a volume fraction of the hard-core (<inline-formula> <tex-math>$f_{\\mathrm {h}}$ </tex-math></inline-formula>) of 0.43. The <inline-formula> <tex-math>$(BH)_{\\max }$ </tex-math></inline-formula> of the hexaferrite (SrFe12O19)/soft-shell (1.9 T) nanomagnet can be improved from 5.8 (single hexaferrite phase) to 20 MGOe. This approach achieves the desired <inline-formula> <tex-math>$(BH)_{\\max }$ </tex-math></inline-formula> of the rare-earth(RE)-free permanent magnet, thereby tackling issues related to RE mineral security and unstable supply chains.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"61 9","pages":"1-9"},"PeriodicalIF":1.9000,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Analytical Maximum Energy Product (BH)max Model for Rare-Earth-Free Magnets: Core–Shell Nanostructure\",\"authors\":\"Yang-Ki Hong;Seok Bae;Jihoon Park;Minyeong Choi;Won-Cheol Lee;Chang-Dong Yeo;Md Abdul Wahed;Kisuk Lee;Haein Yim-Choi;Woo-Young Lee\",\"doi\":\"10.1109/TMAG.2025.3576933\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"This article presents an analytical model for the maximum energy product [<inline-formula> <tex-math>$(BH)_{\\\\max }$ </tex-math></inline-formula>] in core–shell structured magnetic exchange-coupled nanomagnets. The model was validated by comparing its results to the <inline-formula> <tex-math>$(BH)_{\\\\max }$ </tex-math></inline-formula> from core–shell magnets reported in the literature. This approach can serve as a universal model for designing core–shell magnets that achieve the desired <inline-formula> <tex-math>$(BH)_{\\\\max }$ </tex-math></inline-formula>. The <inline-formula> <tex-math>$(BH)_{\\\\max }$ </tex-math></inline-formula> was determined under two distinct nucleation field (<inline-formula> <tex-math>$H_{\\\\mathrm {N}}$ </tex-math></inline-formula>) conditions: <inline-formula> <tex-math>$H_{\\\\mathrm {N}} \\\\le M_{\\\\mathrm {r}}$ </tex-math></inline-formula>/2 and <inline-formula> <tex-math>$H_{\\\\mathrm {N}} \\\\ge M_{\\\\mathrm {r}}$ </tex-math></inline-formula>/2, where <inline-formula> <tex-math>$M_{\\\\mathrm {r}}$ </tex-math></inline-formula> is the remanent magnetization. In addition, two different values of magnetic hysteresis loop squareness (SQ <inline-formula> <tex-math>$= M_{\\\\mathrm {r}}$ </tex-math></inline-formula>/<inline-formula> <tex-math>$M_{\\\\mathrm {S}}$ </tex-math></inline-formula>) were used: 1.0 and 0.7. The soft magnetic shell’s remanent magnetic flux density (<inline-formula> <tex-math>$B_{\\\\mathrm {r}}$ </tex-math></inline-formula>) ranged from 0.7 to 2.2 T, while the core diameter (<inline-formula> <tex-math>$D_{\\\\mathrm {h}}$ </tex-math></inline-formula>) varied between 50 and 250 nm in this <inline-formula> <tex-math>$(BH)_{\\\\max }$ </tex-math></inline-formula> model. The low-temperature phase (LTP) MnBi-core/soft-shell nanomagnet can achieve a <inline-formula> <tex-math>$(BH)_{\\\\max }$ </tex-math></inline-formula> of 40 MGOe at a <inline-formula> <tex-math>$B_{\\\\mathrm {r}}$ </tex-math></inline-formula> of 1.6 T, with a shell thickness (<inline-formula> <tex-math>$\\\\delta _{\\\\mathrm {S}}$ </tex-math></inline-formula>) of 40 nm, a <inline-formula> <tex-math>$D_{\\\\mathrm {h}}$ </tex-math></inline-formula> of 250 nm, and a volume fraction of the hard-core (<inline-formula> <tex-math>$f_{\\\\mathrm {h}}$ </tex-math></inline-formula>) of 0.43. The <inline-formula> <tex-math>$(BH)_{\\\\max }$ </tex-math></inline-formula> of the hexaferrite (SrFe12O19)/soft-shell (1.9 T) nanomagnet can be improved from 5.8 (single hexaferrite phase) to 20 MGOe. This approach achieves the desired <inline-formula> <tex-math>$(BH)_{\\\\max }$ </tex-math></inline-formula> of the rare-earth(RE)-free permanent magnet, thereby tackling issues related to RE mineral security and unstable supply chains.\",\"PeriodicalId\":13405,\"journal\":{\"name\":\"IEEE Transactions on Magnetics\",\"volume\":\"61 9\",\"pages\":\"1-9\"},\"PeriodicalIF\":1.9000,\"publicationDate\":\"2025-06-05\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"IEEE Transactions on Magnetics\",\"FirstCategoryId\":\"5\",\"ListUrlMain\":\"https://ieeexplore.ieee.org/document/11026035/\",\"RegionNum\":3,\"RegionCategory\":\"工程技术\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"ENGINEERING, ELECTRICAL & ELECTRONIC\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"IEEE Transactions on Magnetics","FirstCategoryId":"5","ListUrlMain":"https://ieeexplore.ieee.org/document/11026035/","RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"ENGINEERING, ELECTRICAL & ELECTRONIC","Score":null,"Total":0}
Analytical Maximum Energy Product (BH)max Model for Rare-Earth-Free Magnets: Core–Shell Nanostructure
This article presents an analytical model for the maximum energy product [$(BH)_{\max }$ ] in core–shell structured magnetic exchange-coupled nanomagnets. The model was validated by comparing its results to the $(BH)_{\max }$ from core–shell magnets reported in the literature. This approach can serve as a universal model for designing core–shell magnets that achieve the desired $(BH)_{\max }$ . The $(BH)_{\max }$ was determined under two distinct nucleation field ($H_{\mathrm {N}}$ ) conditions: $H_{\mathrm {N}} \le M_{\mathrm {r}}$ /2 and $H_{\mathrm {N}} \ge M_{\mathrm {r}}$ /2, where $M_{\mathrm {r}}$ is the remanent magnetization. In addition, two different values of magnetic hysteresis loop squareness (SQ $= M_{\mathrm {r}}$ /$M_{\mathrm {S}}$ ) were used: 1.0 and 0.7. The soft magnetic shell’s remanent magnetic flux density ($B_{\mathrm {r}}$ ) ranged from 0.7 to 2.2 T, while the core diameter ($D_{\mathrm {h}}$ ) varied between 50 and 250 nm in this $(BH)_{\max }$ model. The low-temperature phase (LTP) MnBi-core/soft-shell nanomagnet can achieve a $(BH)_{\max }$ of 40 MGOe at a $B_{\mathrm {r}}$ of 1.6 T, with a shell thickness ($\delta _{\mathrm {S}}$ ) of 40 nm, a $D_{\mathrm {h}}$ of 250 nm, and a volume fraction of the hard-core ($f_{\mathrm {h}}$ ) of 0.43. The $(BH)_{\max }$ of the hexaferrite (SrFe12O19)/soft-shell (1.9 T) nanomagnet can be improved from 5.8 (single hexaferrite phase) to 20 MGOe. This approach achieves the desired $(BH)_{\max }$ of the rare-earth(RE)-free permanent magnet, thereby tackling issues related to RE mineral security and unstable supply chains.
期刊介绍:
Science and technology related to the basic physics and engineering of magnetism, magnetic materials, applied magnetics, magnetic devices, and magnetic data storage. The IEEE Transactions on Magnetics publishes scholarly articles of archival value as well as tutorial expositions and critical reviews of classical subjects and topics of current interest.