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arXiv 1308.2016cond-mat.supr-con
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非常规超导体应用的挑战和机遇

Challenges and opportunities for applications of unconventional superconductors

Alex Gurevich

摘要:

自从发现高$T_c$铜氧化物以来,对新超导体的探索已经转向具有更低载流子密度和竞争磁和电荷密度波阶的更各向异性、强相关的材料。虽然这些材料特征增强了超导关联,但它们也导致在液氮(和更高)温度和强磁场下的应用的严重问题,使得诸如临界温度$T_c$和上临界场$H_{c2}$的常规特性不再是主要的优点参数。这是因为强烈的波动的序参量,热激活跳跃的钉扎涡和电磁粒度,已经建立了广泛的调查后,铜酸盐和铁基超导体。在本文中,我给这些机制的电力和磁铁的应用至关重要的概述,并讨论了材料的限制,必须满足,以使超导体在高温和磁场有用。这些限制在更高的温度和磁场下变得越来越重要,特别是对于在室温下工作的尚未发现的超导体。在这种情况下,超导体的性能将受到序参量的破坏性波动的限制,因此降低这些波动的更高的超流密度和更弱的电子各向异性可能比更高的$T_c$变得更加重要。

英文摘要:

Since the discovery of high-$T_c$ cuprates the quest for new superconductors has shifted toward more anisotropic, strongly correlated materials with lower carrier densities and competing magnetic and charge density wave orders. While these materials features enhance superconducting correlations, they also result in serious problems for applications at liquid nitrogen (and higher) temperatures and strong magnetic fields, so that such conventional characteristics as the critical temperature $T_c$ and the upper critical field $H_{c2}$ are no longer the main parameters of merit. This happens because of strong fluctuations of the order parameter, thermally-activated hopping of pinned vortices and electromagnetic granularity, as has been established after extensive investigations of cuprates and Fe-based superconductors. In this paper I give an overview of these mechanisms crucial for power and magnet applications and discuss the materials restrictions which have to be satisfied in order to make superconductors useful at high temperatures and magnetic fields. These restrictions become more and more essential at higher temperatures and magnetic fields, particularly for the yet-to-be-discovered superconductors operating at room temperatures. In this case the performance of superconductors will be limited by destructive fluctuations of the order parameter so higher superfluid density and weaker electronic anisotropy which reduce these fluctuations can become far more important than higher $T_c$.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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