Joint study on application of oxide superconducting films.

氧化物超导薄膜应用联合研究。

• 批准号: 03044025
• 负责人: OHSHIMA Shigetoshi
• 金额: $ 0.64万
• 依托单位: Yamagata University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for international Scientific Research
• 财政年份: 1991
• 资助国家: 日本
• 起止时间: 1991 至 无数据
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-03044025/
• 关键词: Oxide superconducting films; Sputtering; MOCVD; Surface resistance

The realization of high frequency devices using oxide superconductors is very important to prepare small surface resistance films. High quality films have small Rs values. The purpose of joint study between Yamagata University and nuclear research center of Karlsruhe is as follows.(1) Establishment of the preparation technique for high quality films.The high quality films are prepared by MOCVD method in Yamagata University, and by magnetron sputtering with a cylindrical target in nuclear research center of Karlsruhe. We get slightly large-area YBCO thin films (50X50mm^2) by MOCVD and epitaxial films by sputtering.(2) Establishment of the measuring system of surface impedance.The surface impedance of superconducting films is measured by a strip-line resonating method. The Rsvalues of BSCCO and YBCO films decrease below superconducting transition temperature and the value of BSCCO at superconducting state was about 5mOMEGA. .(3) Buffer layerSmall dielectric-constant substrates are needed for high frequency devices. The dielectric constant of Si and sapphire is small, however these substrates easily react on YBCO. We study the buffer layer, NdGaO_3, which protect the reaction between substrate and YBCO. We prepared c-axis oriented NdGaO_3 films on Si substrate by sputtering.

利用氧化物超导体实现高频器件对于制备小表面电阻薄膜非常重要。高品质薄膜的卢比值较小。山形大学与卡尔斯鲁厄核研究中心联合研究的目的如下：(1)建立高质量薄膜的制备技术。高质量薄膜是在山形大学采用MOCVD方法制备的，在卡尔斯鲁厄核研究中心采用磁控溅射圆柱形靶材制备的。采用MOCVD法制备了小面积YBCO薄膜(50X50mm^2)，并采用溅射法制备了外延薄膜。(2)表面阻抗测量系统的建立。采用带状线谐振法测量了超导薄膜的表面阻抗。 BSCCO和YBCO薄膜的Rs值在低于超导转变温度时降低，超导态BSCCO值约为5mΩ。 (3)缓冲层高频器件需要小型介电常数基板。 Si和蓝宝石的介电常数较小，但这些衬底很容易在YBCO上发生反应。我们研究了缓冲层NdGaO_3，它保护衬底和YBCO之间的反应。采用溅射方法在Si衬底上制备了c轴取向的NdGaO_3薄膜。

项目成果

S.Ohshima: "Surface Resistance of the Bi_2Sr_2Ca_1Cu_2O_y Strip Lines made from green sheet" Jpn.J.Appl.Phys. 31. (1992)

S.Ohshima：“由生片制成的 Bi_2Sr_2Ca_1Cu_2O_y 带状线的表面电阻”Jpn.J.Appl.Phys。