Electron Holography for Advanced Characterization of Permanent Magnets: Demagnetization Field Mapping and Enhanced Precision in Phase Analysis.

IF 4.3 3区材料科学 Q2 CHEMISTRY, MULTIDISCIPLINARY Nanomaterials Pub Date : 2024-12-20 DOI:10.3390/nano14242046

Sujin Lee

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Abstract

This review explores a method of visualizing a demagnetization field (H_d) within a thin-foiled Nd₂Fe₁₄B specimen using electron holography observation. Mapping the H_d is critical in electron holography as it provides the only information on magnetic flux density. The H_d 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.

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电子全息技术用于永磁体的高级表征：退磁场映射和相位分析精度的提高。

本文探讨了一种利用电子全息术观察薄膜Nd2Fe14B试样内退磁场（Hd）的方法。绘制Hd在电子全息术中是至关重要的，因为它提供了磁通量密度的唯一信息。该方法得到的Nd2Fe14B薄膜内部的高清图与微磁模拟结果吻合较好，为其矫顽力的研究提供了有价值的见解。此外，本文还研究了小波隐马尔可夫模型（WHMM）在薄膜Nd2Fe14B晶体噪声抑制中的应用。结果表明，由于电子全息图在空间分辨率要求的最窄条纹间距下的可视性较差，在重建的相位图像中人工相位跳变得到了明显的抑制。这些技术大大提高了相分析的精度，适用于广泛的磁性材料，实现更准确的磁性表征。

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来源期刊

Nanomaterials NANOSCIENCE & NANOTECHNOLOGY-MATERIALS SCIENCE, MULTIDISCIPLINARY

CiteScore

8.50

自引率

9.40%

发文量

3841

审稿时长

14.22 days

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.