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Development of New High-Tc Superconductors with Record-High Tc by Synthesis under High Oxygen Pressures

通过高氧压力合成开发具有创纪录高温温度的新型高温超导体

基本信息

批准号：
10650820
负责人：
SHIMOYAMA Jun-ichi
金额：
$ 2.24万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

项目摘要

In this study project which continued for 2 years, synthesis of new high-TィイD2cィエD2 superconductors with record-high TィイD2cィエD2 have been attempted by applying heat-treatments under very high oxygen pressures. The main apparatus introduced in this study was an electric furnace equipped with high oxygen pressure generating system. Using this apparatus, high oxygen pressure up to 50MPa was achieved. The mercury-based system was adopted as a candidate mother material for new superconducting compounds, because of its high TィイD2cィエD2. However, all the various attempts of chemical substitution for this system have been failed in terms of a new record-high TィイD2cィエD2. The obtained highest TィイD2cィエD2 was as high as 135K, which is only a tie-record. On the other hand, new material research was continued for other systems and a new iron-based superconductor was discovered. Its chemical composition was FeSrィイD22ィエD2RECuィイD22ィエD2OィイD2yィエD2 (RE : rare earth element). It was found that partial substitution of iron for copper was suppressed by annealing under moderately reducing conditions, resulting in appearance of superconductivity after annealing under high oxygen pressures, 〜40MPa Its TィイD2cィエD2 is approximately 60K at the present stage, however, further increase will be achieved by optimization of synthesis procedures and conditions. It should be noted that this new TィイD2cィエD2 material is the first compound which contains 3d transition metal other than copper as a main constituent metal element. Therefore, the present discovery is believed to give a new guiding principle for material design of new high-TィイD2cィエD2 superconductors as well as exotic magnetic compounds.

在这个持续两年的研究项目中，尝试通过在非常高的氧压下进行热处理来合成具有创纪录高T 'イD2 c' D2的新型高T 'イD2 c' D2超导体。本研究所用的主要设备是一台配有高压氧发生系统的电炉。使用该装置，获得了高达50MPa的高氧气压力。汞基体系由于具有较高的T_（10）D_（2c）T_（10）D_（2c），被作为新型超导化合物的候选母体材料。然而，所有化学替代该系统的各种尝试都失败了，因为新的历史最高的T_（2c）_（2d）。所获得的最高T_（20）D_（20）D_（20）D_（20）高达135K，这只是一个并列记录。另一方面，对其他系统的新材料研究继续进行，并发现了一种新的铁基超导体。其化学成分为FeSr D22 D2RECu D22 D2O D2y D2（RE：稀土元素）。结果表明，在适度还原条件下退火，抑制了铁对铜的部分替代，导致在高氧压下退火后出现超导电性，其T_（max）D_（2c）T_（max）D_（2c）D_（2c）目前约为60K，但通过优化合成工艺和条件，可进一步提高。应该注意，这种新的T ↓ [2] D2c ↓ [3] D2材料是第一种含有铜以外的3d过渡金属作为主要构成金属元素的化合物。因此，本发现被认为是一个新的指导原则，为新的高T超导体的D2c的D2c的超导体以及奇异磁性化合物的材料设计。