{"title":"Electron Holography for Advanced Characterization of Permanent Magnets: Demagnetization Field Mapping and Enhanced Precision in Phase Analysis.","authors":"Sujin Lee","doi":"10.3390/nano14242046","DOIUrl":null,"url":null,"abstract":"<p><p>This review explores a method of visualizing a demagnetization field (<i>H<sub>d</sub></i>) within a thin-foiled Nd<sub>2</sub>Fe<sub>14</sub>B specimen using electron holography observation. Mapping the <i>H<sub>d</sub></i> is critical in electron holography as it provides the only information on magnetic flux density. The <i>H<sub>d</sub></i> map within a Nd<sub>2</sub>Fe<sub>14</sub>B thin foil, derived from this method, showed good agreement with the micromagnetic simulation result, providing valuable insights related to coercivity. Furthermore, this review examines the application of the wavelet hidden Markov model (WHMM) for noise suppression in thin-foiled Nd<sub>2</sub>Fe<sub>14</sub>B crystals. The results show significant suppression of artificial phase jumps in the reconstructed phase images due to the poor visibility of electron holograms under the narrowest fringe spacing required for spatial resolution in electron holography. These techniques substantially enhance the precision of phase analysis and are applicable to a wide range of magnetic materials, enabling more accurate magnetic characterization.</p>","PeriodicalId":18966,"journal":{"name":"Nanomaterials","volume":"14 24","pages":""},"PeriodicalIF":4.4000,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11676280/pdf/","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Nanomaterials","FirstCategoryId":"88","ListUrlMain":"https://doi.org/10.3390/nano14242046","RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
This review explores a method of visualizing a demagnetization field (Hd) within a thin-foiled Nd2Fe14B specimen using electron holography observation. Mapping the Hd is critical in electron holography as it provides the only information on magnetic flux density. The Hd map within a Nd2Fe14B thin foil, derived from this method, showed good agreement with the micromagnetic simulation result, providing valuable insights related to coercivity. Furthermore, this review examines the application of the wavelet hidden Markov model (WHMM) for noise suppression in thin-foiled Nd2Fe14B crystals. The results show significant suppression of artificial phase jumps in the reconstructed phase images due to the poor visibility of electron holograms under the narrowest fringe spacing required for spatial resolution in electron holography. These techniques substantially enhance the precision of phase analysis and are applicable to a wide range of magnetic materials, enabling more accurate magnetic characterization.
期刊介绍:
Nanomaterials (ISSN 2076-4991) is an international and interdisciplinary scholarly open access journal. It publishes reviews, regular research papers, communications, and short notes that are relevant to any field of study that involves nanomaterials, with respect to their science and application. Thus, theoretical and experimental articles will be accepted, along with articles that deal with the synthesis and use of nanomaterials. Articles that synthesize information from multiple fields, and which place discoveries within a broader context, will be preferred. There is no restriction on the length of the papers. Our aim is to encourage scientists to publish their experimental and theoretical research in as much detail as possible. Full experimental or methodical details, or both, must be provided for research articles. Computed data or files regarding the full details of the experimental procedure, if unable to be published in a normal way, can be deposited as supplementary material. Nanomaterials is dedicated to a high scientific standard. All manuscripts undergo a rigorous reviewing process and decisions are based on the recommendations of independent reviewers.