【公開日：2023.07.31】【最終更新日：2023.05.16】

課題データ / Project Data

課題番号 / Project Issue Number

22UT0082

利用課題名 / Title

セラミックス欠陥の原子構造と機能特性

利用した実施機関 / Support Institute

東京大学 / Tokyo 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）革新的なエネルギー変換を可能とするマテリアル/Materials enabling innovative energy conversion（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

電子顕微鏡/Electron microscopy,熱電材料/ Thermoelectric material,エネルギー貯蔵/ Energy storage,原子層薄膜/ Atomic layer thin film,ナノ粒子/ Nanoparticles,原子薄膜/ Atomic thin film

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)

Lin Jinghuang

所属名 / Affiliation

東京大学

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）機器利用/Equipment Utilization（副 / Sub）-

利用した主な設備 / Equipment Used in This Project

UT-002：軽元素対応型超高分解能走査透過型電子顕微鏡（Cs-STEM）
UT-004：環境対応型超高分解能走査透過型電子顕微鏡

報告書データ / Report

概要（目的・用途・実施内容）/ Abstract (Aim, Use Applications and Contents)

(LaAlO₃)_0.3(Sr₂AlTaO₆)_0.7 (LSAT) has the perovskite structure, where Sr or La element occupies the A-site and Al or Ta occupies the B-site within the unit cell. In practical applications, LSAT is applied as substrates for many important energy and quantum related materials. For high-temperature superconducting films grown on LSAT, the introduction of grain boundaries (GBs) alters superconducting current, which plays a key role in determining the macroscopic properties of epitaxial films. Although some investigations reported on introducing artificial GBs on films by bicrystal LSAT substrates for superconduction materials, few studies have been reported on the atomistic insight into the GB structures in LSAT. For better utilization and design of GB structures, it is a prerequisite to fully investigate atomic structure and element distribution in LSAT GBs. Since there are enormous varieties of GBs in polycrystals, well-defined coincidence site lattice (CSL) GBs by the bicrystal method provide a model for investigating the microstructures in specific CSL GBs. Herein, we investigate the atomic structure and element distribution at the LSAT Σ17(410)/[001] GB, where by atomic-resolution STEM and EDS to elucidate the atomic structure and element distribution.

実験 / Experimental

To fabricate bicrystal, two LSAT single crystals were firstly bonded by diffusion bonding methods at 1600 °C for 15 h in air. The TEM specimen of Σ17(410)/[001] GB was obtained by mechanical polishing and Ar-ion beam milling. The GBs were then characterized by atomic-resolution STEM.

結果と考察 / Results and Discussion

Considering the complexity of the element compositions in LSAT, we firstly investigate the atomic structure and element distribution at the bulk areas, as shown in Figure 1. Figure 1a and b exhibited the typical high-angle annular dark-field (HAADF) and annular bright-field (ABF) images, which were simultaneously acquired by viewing along [001] zone axis. Owing to the Z contrast in HAADF (Z is atomic number), the bright spots in Figure 1a correspond to the metal atoms (La, Sr, Al, Ta). While ABF approach has been demonstrated to simultaneously image light and heavy atoms, these extra spots in Figure 1b were identified as O columns. Since Sr or La element occupies the A-site and Al or Ta occupies the B-site LSAT, the average Z values for A-site and B site are 43.6 and 34.2, by considering the theoretical stoichiometric ratio. Therefore, it is very hard to distinguish or determine the position of the metal elements from HAADF, and further STEM-EDS study is necessary in future. At the GB, we found it composed of periodically arranged structural units.

図・表・数式 / Figures, Tables and Equations

Figure 1 (a) HAADF-STEM and (b) ABF-STEM image of the LSAT

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)

1. Qian Yang, Solid‐State Electrochemical Thermal Transistors, Advanced Functional Materials, 33, (2023).
   DOI: 10.1002/adfm.202214939
   
2. Binjie Chen, Orthorhombic distortion-induced anatase-like optoelectronic properties of rutile TiO2, Journal of Applied Physics, 132, (2022).
   DOI: 10.1063/5.0119725
   

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