【公開日：2023.07.28】【最終更新日：2023.05.25】
課題データ / Project Data
課題番号 / Project Issue Number
22TU0107
利用課題名 / Title
鉄系超伝導体のフラックスピンニング研究
利用した実施機関 / Support Institute
東北大学 / Tohoku Univ.
機関外・機関内の利用 / External or Internal Use
内部利用（ARIM事業参画者以外）/Internal Use (by non ARIM members)
技術領域 / Technology Area
【横断技術領域 / Cross-Technology Area】（主 / Main）計測・分析/Advanced Characterization（副 / Sub）-
【重要技術領域 / Important Technology Area】（主 / Main）高度なデバイス機能の発現を可能とするマテリアル/Materials allowing high-level device functions to be performed（副 / Sub）-
キーワード / Keywords
超伝導材料・物質・素子, 合金超伝導体,電子顕微鏡/Electron microscopy,集束イオンビーム/Focused ion beam
利用者と利用形態 / User and Support Type
利用者名（課題申請者）/ User Name (Project Applicant)
LUO JUNYI
所属名 / Affiliation
東北大学 金属材料研究所
共同利用者氏名 / Names of Collaborators in Other Institutes Than Hub and Spoke Institutes
ARIM実施機関支援担当者 / Names of Collaborators in The Hub and Spoke Institutes
利用形態 / Support Type
（主 / Main）技術代行/Technology Substitution（副 / Sub）-
利用した主な設備 / Equipment Used in This Project
TU-504：超高分解能透過電子顕微鏡
TU-507：集束イオンビーム加工装置
TU-508：集束イオンビーム加工装置
報告書データ / Report
概要（目的・用途・実施内容）/ Abstract (Aim, Use Applications and Contents)
This research focuses on the “122” type iron-based superconductors Ba1-xKxFe2As2 (Ba122). Extremely small anisotropy, high upper critical field and moderate transfer temperature make Ba122 favorable for magnet application. The max critical current density Jc of Ba122 tape has achieved the order of 105 A/cm2, which met the need for practical applications but is still not enough for the next-generation magnets. Moreover, many Jc properties and mechanical properties remain unknown for Ba122 tapes. These unknowns restrict the Jc improvement and leave deficiency for practical applications. Through the measurement and analysis of Jc properties for Ba122, an anomalous Jc anisotropy has been observed. By comparing it to the previous study and calculating to reproduce the Jc anisotropy, a possibility that spherical pinning centers may exist in Ba122 tapes came up. As an additional pinning mechanism, the spherical pinning centers lead to the anomalous Jc anisotropy. To confirm the existence of spherical pinning centers and provide evidence to the calculation theory, the microstructure of Ba122 tapes is needed to be observed and analyzed. It is expected to find spherical components working as pinning centers using TEM.
実験 / Experimental
After removing the sheathes of the samples, the left superconducting cores were processed by Focused Ion Beam (FIB) milling or Ion Slicer. Then the samples were observed by Transmission Electron Microscopy (TEM).
結果と考察 / Results and Discussion
On the cross-section of the sample processed by Ion Slicer, a lot of defects with strain around them were observed (Fig. 1). They seem to be the spherical pinning centers. At the defects, the lack of iron and arsenic elements was observed (Fig. 2). More analyses are needed to confirm whether the defects with strain are the expected spherical pinning centers. How to introduce these defects consciously is also the future task.
図・表・数式 / Figures, Tables and Equations
Fig. 1 TEM micrograph of a cross section of the Ba122 superconducting core.
Fig. 2 EDS mapping images of a defect. A lack of Fe and As was observed.
その他・特記事項（参考文献・謝辞等） / Remarks(References and Acknowledgements)
成果発表・成果利用 / Publication and Patents
論文・プロシーディング（DOIのあるもの） / DOI (Publication and Proceedings)
口頭発表、ポスター発表および、その他の論文 / Oral Presentations etc.
特許 / Patents
特許出願件数 / Number of Patent Applications：0件
特許登録件数 / Number of Registered Patents：0件