Institute for Superconducting and Electronic Materials, Australian Institute for Innovative Materials, University of Wollongong, North Wollongong, NSW 2522, Australia.
1] Institute for Superconducting and Electronic Materials, Australian Institute for Innovative Materials, University of Wollongong, North Wollongong, NSW 2522, Australia [2] Department of Physics, Ferdowsi University of Mashhad, Mashhad, Iran.
Sci Rep. 2015 Feb 3;5:8213. doi: 10.1038/srep08213.
Pressure is well known to significantly raise the superconducting transition temperature, Tc, in both iron pnictides and cuprate based superconductors. Little work has been done, however, on how pressure can affect the flux pinning and critical current density in the Fe-based superconductors. Here, we propose to use hydrostatic pressure to significantly enhance flux pinning and Tc in polycrystalline pnictide bulks. We have chosen Sr4V2O6Fe2As2 polycrystalline samples as a case study. We demonstrate that the hydrostatic pressure up to 1.2 GPa can not only significantly increase Tc from 15 K (underdoped) to 22 K, but also significantly enhance the irreversibility field, Hirr, by a factor of 4 at 7 K, as well as the critical current density, Jc, by up to 30 times at both low and high fields. It was found that pressure can induce more point defects, which are mainly responsible for the Jc enhancement. Our findings provide an effective method to significantly enhance Tc, Jc, Hirr, and the upper critical field, Hc2, for other families of Fe-based superconductors in the forms of wires/tapes, films, and single crystal and polycrystalline bulks.
压力被公认为可以显著提高铁基磷化物和铜基高温超导体的超导转变温度 Tc。然而，关于压力如何影响铁基超导体中的磁通钉扎和临界电流密度的研究还很少。在这里，我们提出使用静水压力来显著增强多晶磷化物块状体中的磁通钉扎和 Tc。我们选择 Sr4V2O6Fe2As2 多晶样品作为案例研究。我们证明，高达 1.2 GPa 的静水压力不仅可以将 Tc 从 15 K（欠掺杂）显著提高到 22 K，而且可以将 7 K 时的不可逆场 Hirr 提高 4 倍，还可以将低场和高场下的临界电流密度 Jc 提高高达 30 倍。研究发现，压力可以诱导更多的点缺陷，这是导致 Jc 增强的主要原因。我们的研究结果为其他形式的铁基超导体（如线材/带材、薄膜、单晶和多晶块状体）提供了一种有效提高 Tc、Jc、Hirr 和上临界场 Hc2 的方法。
