【公開日：2024.07.25】【最終更新日：2024.06.24】
課題データ / Project Data
課題番号 / Project Issue Number
23JI0021
利用課題名 / Title
A study of high temperature superconductor heterostructures by STEM observation
利用した実施機関 / Support Institute
北陸先端科学技術大学院大学 / JAIST
機関外・機関内の利用 / External or Internal Use
外部利用/External Use
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）量子・電子制御により革新的な機能を発現するマテリアル/Materials using quantum and electronic control to perform innovative functions
キーワード / Keywords
Superconducting materials; Thin films; Surface and Interface; Scanning transmission electron microscopy,電子顕微鏡/ Electronic microscope,表面・界面・粒界制御/ Surface/interface/grain boundary control,高品質プロセス材料/技術/ High quality process materials/technique,超伝導/ Superconductivity
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)
Jia Jiqiang
所属名 / Affiliation
Advanced Analysis and Testing Center, Xi'An University of Technology
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
Oshima Yoshifumi
利用形態 / Support Type
（主 / Main）技術補助/Technical Assistance（副 / Sub）-
利用した主な設備 / Equipment Used in This Project
報告書データ / Report
概要（目的・用途・実施内容）/ Abstract (Aim, Use Applications and Contents)
The purpose of this project is to investigate the crystal structure, electrical characteristics, and oxygen vacancies distribution of high-temperature superconducting films under different experimental conditions. Specifically, the crystal structure, electrical properties, and oxygen vacancy distribution of Bi2Sr2CaCu2O8+x/Nb:SrTiO3(Bi-2212/NSTO) and Nd2-yCeyCuO4(NCCO)/ YBCO heterostructures was observed using the spherical aberration corrected transmission electron microscope (JEM-ARM200F), and the mechanism of resistive switching (RS) effect was analyzed.
実験 / Experimental
Observing the crystal structure and oxygen vacancies distribution of superconductors using the STEM mode of ARM200 (Applied voltage is 200kV).
結果と考察 / Results and Discussion
STEM images show the epitaxial growth of high-temperature superconductors and their heterostructures on a LaAlO3 substrate. The changes in the distribution of oxygen vacancies in Bi-2212 before (in the high resistance state) and after (in the low resistance state) resistive switching (RS) effect were studied using electron energy loss spectrum (EELS) in STEM mode. In the low resistance state, there was an increase in the number of oxygen vacancies in Bi-2212 near the Bi-2212/NSTO interface relative to the initial state (high resistance state), attributable to the influence of the bias electric field (as shown in Figs. 1(a)-(c)). The migration and redistribution of oxygen vacancies lead to changes in the interface barrier height, thereby inducing the occurrence of the RS effect. Furthermore, the interface characteristics of YBCO/NCCO bilayer superconducting structures were investigated. It was observed that the peak of the Ba element at the interface gradually weakened rather than disappearing directly, with a depth range of approximately 5nm from peak reduction to complete disappearance, possibly corresponding to the diffusion depth of Ba from YBCO to NCCO during the heat treatment process. Similarly, the peak intensity of Nd also gradually decreased, with a diffusion depth consistent with that of Ba (approximately 5nm, as shown in Figs. 2(a)-(d)). Lastly, the distribution of oxygen vacancies in YBCO prepared via different processes were explored. Atomic-level resolution EELS testing revealed that oxygen vacancies predominantly appeared on the Cu-O chain of YBCO, with no apparent oxygen vacancy peaks detected on the Cu-O plane.
図・表・数式 / Figures, Tables and Equations
Fig. 1 EELS spectrum of oxygen at the Bi-2212/NSTO interface before (a) and after (b) the RS test
Fig. 2 EELS spectrum of Ba element in YBCO/NCCO structure
その他・特記事項（参考文献・謝辞等） / Remarks(References and Acknowledgements)
I express my gratitude to the ARIM project for their support of my research, and extend my thanks to Professor Oshima Yoshifumi and JAIST for their valuable assistance.
(1) J.Q. Jia, C. Liu, M.J. Guo, et al.: Ceram. Int. 47, 32068-32074 (2021).
(2) M.H. Shen, L. Lei, G.Y. Zhao, et al.: Supercon. 4, 100030 (2022).
(3) J.Q. Jia, C. Liu, M.J. Guo, et al.: Ceram. Int. 47, 27503-27510 (2021).
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.
- Jiqiang Jia, Minghu Shen, Chen Liu, Gaoyang Zhao, Li Lei, “I–V characteristics of the GdBa2Cu3O7-x/YBa2Cu3O7-ẟ and Bi2Sr2CaCu2O8+σ/YBa2Cu3O7-ẟ heterostructures” the 9th International Symposium on Organic and Inorganic Electronic Materials and Related Nanotechnologies International Academic Conference (EM-NANO 2023)(Kanazawa), June 5, 2023
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