Study of Strong Superconducting Coupling between High Tc and Low Tc Superconducting layers by Interface-Control

高温与低温超导层间强超导耦合的界面控制研究

• 批准号: 13650016
• 负责人: TERADA Norio
• 金额: $ 2.37万
• 依托单位: Kagoshima University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13650016/
• 关键词: High Tc Superconductors; Surface-Interface Control; Superconducting Order Parameter; Active Oxygen beam; Photoemission Spectroscopy; Proximity Effect; 金属系超伝導体; 超伝導オーダーパラメーター; 電子状態接続

An enhancement of superconducting coupling between high temperature superconducting (HTS) layer and low temperature one, which is seriously suppressed in usual interfaces by structural defects and interface-reactions, has been attempted by controlling electronic structure of the HTIS-side region. In the present project, YBa_2Cu_3O_<7-δ> (YBCO) films was selected as the HTS layer. In the first stage, for developing an intrinsic surface nature with the original amplitude of the order parameter, we have adopted a cleaning of the YBCO surface by an annealing under an intensive atomic oxygen beam. This treatment yielded an elimination of carbon-related impurities and a development of metallic feature in in-situ ultraviolet photoemission spectra. The height of the Fermi edge of the treated a-, and c-YBCO films was as high as 10 % of Cu 3d characterized peak in their valence band, which was comparable with that of vacuum-cleaved single crystals at a cryogenic temperature. The optimum treatmen … More t condition in the present study was as follows : an annealing temperature of 450 ℃ and a flux density of the atomic oxygen above 5x10^<15> atoms/cm^2・sec. Because of the high electron density of states, a contact resistibity between the optimally treated c-YBCO surface and in-situ deposited Au reached in the range of 1〜5x10^<-9> Ω・cm^2. A high critical current density up to 7x10^5 a/cm^2 at 4.2 K was also achieved in the Pb-In/Ag ; 1〜2 nm /Au ; 1〜2 nm /c-YBCO (optimally treated) multiplayer structure. A suppression of tunneling conductance around zero bias was observed in scanning tunneling spectroscopy on the (ultra thin Au)/c-YBCO surface at 4.2 K, which could be explained by propagation of superconducting proximity effect through the Au layer. The obtained transport properties meet requirements in design of integrated circuits. And the results also indicate an usefulness of the control of the surface of HTS layers by using both the atomic oxygen treatment and in-situ characterization of the electronic structure. Less

通过控制HTIS边区域的电子结构，尝试了高温超导（HTS）层（HTS）层和低温层之间的超导耦合的增强，这通过结构缺陷和界面反应严重抑制。在本项目中，选择了YBA_2CU_3O_ <7-ugu_du_（YBCO）膜作为HTS层。在第一阶段，为了开发具有顺序参数原始幅度的固有表面性质，我们通过在密集的原子氧束下退火来清洁YBCO表面。这种处理产生了与碳相关杂质的排放，并在原位紫外线光发射光谱中发育了金属特征。处理过的A-和c Ybco膜的费米边缘的高度高达其价带中的Cu 3D峰值的10％，在其价值带中，峰值与在低温温度下的真空切割的单晶相当。最佳处理……在本研究中，更多的T条件如下：退火温度为450℃，原子氧的通量密度高于5x10^<15>原子/cm^2 sec。由于状态的高电子密度，在1〜5x10^<-9> ω・CM^2的范围内，经过最佳处理的c Ybco表面和原位AU之间的接触电阻率达到。在PB-IN/AG中，还达到了4.2 K时高达7x10^5 A/CM^2的高临界电流密度； 1-2 nm /au; 1-2 nm /c-ybco（经过最佳处理）多人游戏结构。在4.2 K处的（超薄AU）/c-Ybco表面上的扫描隧道光谱扫描隧道光谱中观察到隧道电导的抑制作用，这可以通过通过AU层传播超导接近效应来解释。获得的运输属性符合集成电路设计的要求。结果还表明，通过使用原子氧处理和电子结构的原子表征，控制HTS层表面的有用性。较少的

项目成果

K.Ohki: "In-situ Characterization of Thermal Stability and Depth Profile of Electronic Structure of Engineered Surfaces of c-axis YBa_2Cu_3O_<7-δ> films"Proc.EUCAS2003. (in press). (2004)

K.Ohki：“c 轴 YBa_2Cu_3O_<7-δ> 薄膜的工程表面的热稳定性和深度剖面的原位表征”Proc.EUCAS2003（印刷中）。

N.Terada, Kotaro Ohki, A.Ohtomi, S.Miyanomae, K.Obara, H.Akoh, H.Sato, T.Yamada, E.Fujimoto: "In-situ characterization of Engineered Surfaces of c-YBCO Films for Sandwich type Junction"IEEE Trans Appl.Supercond.. Vol.13. 813-816 (2003)

N.Terada、Kotaro Ohki、A.Ohtomi、S.Miyanomae、K.Obara、H.Akoh、H.Sato、T.Yamada、E.Fujimoto：“三明治用 c-YBCO 薄膜工程表面的原位表征

K.Eguchi, S.Y.Park, N.Terada, K.Obara: "Cooperative phenomena in super-thin oxide layer on metallic electrode"Trans.of Mat.Res.Soc.Japan. Vol.26 No.4. 1295-1298 (2001)

K.Eguchi、S.Y.Park、N.Terada、K.Obara：“金属电极上超薄氧化层的合作现象”Trans.of Mat.Res.Soc.Japan。

N.Terada, T.Fukida, T.Hayashi, A.Iyo, Y.Tanaka, Y.Kinoue, K.Obara, H.Ihara: "Photoemission Study of Electronic Structure of TI-1223 Superconductors Synthesized under Ambient-and High-Pressure"Trans.Mat.Res.Soc.Japan. vol.26. 1017-1020 (2001)

N.Terada、T.Fukida、T.Hayashi、A.Iyo、Y.Tanaka、Y.Kinoue、K.Obara、H.Ihara：“环境和高温下合成的 TI-1223 超导体电子结构的光电发射研究”

K.Obara et al.: "Collision Processes between Sputtered Particles on High Speed Rotating Substrate and Atomic Mass Dependence of Sticking Coefficient"J.Crystal Growth. (in press). (2001)

K.Obara 等人：“高速旋转基板上溅射粒子之间的碰撞过程和粘附系数的原子质量依赖性”J.Crystal Growth。