权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Synthesis of multilayers of oxide-superconductor/insulator using activated oxygen plasma

使用活性氧等离子体合成多层氧化物超导体/绝缘体

基本信息

批准号：
12650331
负责人：
MICHIKAMI Osamu
金额：
$ 2.18万
依托单位：
Iwate University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12650331/
关键词：
oxide superconductor activated oxygen plasma EuBaCuO thin film oxygen deficiency recovery treatment superconductor insulator multilayer 超電導体・絶縁体多層膜

项目摘要

The "123" high-Tc superconductors are very sensitive to oxygen content and are liable to cause oxygen deficiency. We attempted to establish the methods for recovery treatment of a degraded superconducting thin film and for prevention against degradation of or recovery treatment of a lower-layer superconducting thin film in insulator deposition. The initial plan was to use plasma induced by sputtering and plasma induced by microwaves in this investigation. Though satisfactory results were obtained by the former method, the results obtained by the latter method were not good. Activated oxygen plasma (AOP) through which EuBa_2Cu_3O_7(EBCO) thin films with Tc=90 K were synthesized by DC magnetoron sputtering using a high-quality sintered superconducting target was used as a treating plasma. The results are summarized as follows.a) Recovery treatment for degraded EBCO thin films : When the degraded EBCO was indirectly exposed to AOP, the high-quality characteristics of the film were complet … More ely recovered. The appropriate AOP recovery conditions were annealing temperature of 450-700 ℃, plasma exposing time of more than 30 min and oxygen introducing pressures after annealing (Pox) of above 2 kPa. The AOP recovery treatment technology was newly developed for oxide superconductors.b) Application to insulator/superconductor multi-layers and protective layer : SrTiO_2(STO) and CeO_2 thin films were deposited on as-grown EBCO, and the influence on the lower-layer EBCO was examined. STO caused marked deterioration of the EBCO thin films compared with CeO_2. By means of insertion of 50-Å-thick CeO_2 between EBCO and STO, the degradation of the lower-layer EBCO was mitigated. Though the AOP treatment was effective for recovery of the multi-layer, the degree of recovery depended on STO film thickness and Pox. On the other hand, CeO_2 films were deposited on EBCO films at 500-570 ℃ in AOP, but the lower-layer EBCO did not degenerate. When EBCO with 2000-Å-thick CeO_2 was exposed to the atmosphere with relative humidity of 70 %, the EBCO films exhibited high Tc values for 2 months. Less

“123”高tc超导体对氧含量非常敏感，容易引起缺氧。我们试图建立退化超导薄膜的恢复处理方法，并防止绝缘体沉积中下层超导薄膜的降解或恢复处理。最初的计划是使用溅射诱导等离子体和微波诱导等离子体进行研究。前一种方法得到了令人满意的结果，后一种方法得到的结果并不好。以优质烧结超导靶为处理等离子体，采用直流磁控溅射法制备了Tc= 90k的EuBa_2Cu_3O_7（EBCO）薄膜。结果总结如下：a)降解EBCO薄膜的回收处理：当降解EBCO间接暴露于AOP时，薄膜的优质特性完全，回收率更高。适宜的AOP恢复条件为退火温度450 ~ 700℃，等离子体暴露时间大于30 min，退火后氧引入压力（Pox）大于2 kPa。AOP回收处理技术是氧化超导体的新技术。b)在绝缘子/超导体多层和保护层中的应用：在生长的EBCO上沉积SrTiO_2（STO）和CeO_2薄膜，并考察其对下层EBCO的影响。与CeO_2相比，STO使EBCO薄膜劣化明显。通过在EBCO和STO之间插入50-Å-thick CeO_2，减缓了下层EBCO的降解。虽然AOP处理对多层膜的恢复是有效的，但恢复的程度取决于STO膜厚度和Pox。另一方面，在500 ~ 570℃的AOP温度下，在EBCO薄膜上沉积了CeO_2薄膜，但下层EBCO未发生简并。当含2000-Å-thick CeO_2的EBCO暴露于相对湿度为70%的大气中时，EBCO薄膜在2个月内呈现高Tc值。少