Understanding limiting factors in the performance of high Tc superconductors

了解高温超导体性能的限制因素

• 批准号: EP/C011554/1
• 负责人: John Durrell
• 金额: $ 18.09万
• 依托单位: University of Cambridge
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2006
• 资助国家: 英国
• 起止时间: 2006 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FC011554%2F1
• 关键词: Understanding; limiting; factors; performance; Tc

A superconductor is a material in which electricity can flow without energy loss. This is unlike ordinary metals which waste energy by getting hot due to the interaction between the flowing current and the material. The phenomenon of superconductivity has fascinated scientists and technologists since its discovery over 90 years ago. Unfortunately superconductors only work at low temperatures and there is always a limit to the maximum amount of electricity that can be transported. This explains why, in spite of repeated predictions, we don't yet see superconductors on electricity pylons and in everyday objects.In the last few years however materials, high-Tc superconductors , have been developed which work at temperatures, which while still a long way below freezing, are practical with existing refrigeration technology. Again there is a catch in that these ceramic materials have a granular structure. The granular structure can be thought of as the materials consisting of many individual crystals (similar to quartz or salt) connected together. The individual crystals are termed grains and the interfaces between them are grain boundaries. Unfortunately electricity does not flow well across grain boundaries and this limits the performance of large samples of high-Tc superconductor.The 'grain-boundary' problem is however being overcome by growing the superconductor on a carefully made strip of metal which aligns the ceramic grains so as to allow the current to flow easily. This means that the limiting factor is now not always the grain boundaries in these materials. We have recently shown that there is a cross-over point where the maximum current stops being limited by the grain boundaries and starts being limited by the individual grains. This depends on temperature, strength of any applied magnetic field and also the direction of any applied magnetic field.The final barrier to more widespread use of superconductors is in essence economic, they need to transport more current, more cheaply than the existing technology. My project seeks to understand how the current in the most promising superconducting material is affected by magnetic fields of various orientations and by the way the material is made. I am also intending to isolate individual grains and pairs of grains from these materials to study them and the interfaces between them. This will allow us to understand how new ways of improving the current carrying capacity work in detail and which of these techniques should be used in what combination to produce the best superconductor for each potential application.

超导体是一种电可以在其中流动而没有能量损失的材料。这与普通金属不同，普通金属由于流动电流与材料之间的相互作用而发热，从而浪费能量。超导现象自90多年前被发现以来一直吸引着科学家和技术人员。不幸的是，超导体只能在低温下工作，而且可以传输的最大电量总是有限制的。这就解释了为什么尽管人们一再预言，但我们还没有在电线塔和日常用品中看到超导体。然而，在过去的几年里，人们已经开发出了高温超导体，这种材料在低于冰点的温度下工作，尽管还有很长的路要走，但在现有的制冷技术中是可行的。同样，这些陶瓷材料具有颗粒状结构。粒状结构可以被认为是由许多单独的晶体（类似于石英或盐）连接在一起组成的材料。单个晶体称为晶粒，它们之间的界面称为晶界。不幸的是，电流不能很好地穿过晶粒边界，这限制了高Tc超导体的大样品的性能。然而，通过在精心制作的金属条上生长超导体，使陶瓷颗粒排列整齐，从而使电流容易流动，“晶粒边界”问题被克服了。这意味着限制因素现在并不总是这些材料中的晶界。我们最近已经表明，存在一个交叉点，在该交叉点处，最大电流停止受到晶界的限制，并开始受到单个晶粒的限制。这取决于温度、外加磁场的强度以及外加磁场的方向。更广泛使用超导体的最后一个障碍本质上是经济的，它们需要传输更大的电流，比现有技术更便宜。我的项目旨在了解最有前途的超导材料中的电流如何受到各种方向的磁场以及材料制造方式的影响。我还打算从这些材料中分离出单个颗粒和成对的颗粒，以研究它们以及它们之间的界面。这将使我们能够详细了解提高载流能力的新方法是如何工作的，以及这些技术中的哪一种应该以什么样的组合使用，以生产出适合每种潜在应用的最佳超导体。

项目成果

Mechanisms for enhanced supercurrent across meandered grain boundaries in high-temperature superconductors

• DOI: 10.1063/1.2800255
• 发表时间: 2007-10-15
• 期刊: JOURNAL OF APPLIED PHYSICS
• 影响因子: 3.2
• 作者: Feldmann, D. M.;Holesinger, T. G.;Larbalestier, D. C.
• 通讯作者: Larbalestier, D. C.

Practical vortex diodes from pinning enhanced YBa2Cu3O7-d

来自钉扎增强型 YBa2Cu3O7-d 的实用涡流二极管

• DOI: 10.48550/arxiv.0904.3497
• 发表时间: 2009
• 作者: Harrington S

Application of textured highly alloyed Ni-W tapes for preparing coated conductor architectures

• DOI: 10.1088/0953-2048/23/3/034015
• 发表时间: 2010-03-01
• 期刊: SUPERCONDUCTOR SCIENCE & TECHNOLOGY
• 影响因子: 3.6
• 作者: Huehne, R.;Eickemeyer, J.;Holzapfel, B.
• 通讯作者: Holzapfel, B.