title: Hydrostatic pressure: a very effective approach to significantly enhance critical current density in granular iron pnictide superconductors.
abstract: 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.
authors: Institute for Superconducting and Electronic Materials, Australian Institute for Innovative Materials, University of Wollongong, North Wollongong, NSW 2522, Australia.
authors: Babar
authors: B
authors: Shabbir
authors: Institute for Superconducting and Electronic Materials, Australian Institute for Innovative Materials, University of Wollongong, North Wollongong, NSW 2522, Australia.
authors: Xiaolin
authors: X
authors: Wang
authors: 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.
authors: S R
authors: SR
authors: Ghorbani
authors: Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany.
authors: Chandra
authors: C
authors: Shekhar
authors: Institute for Superconducting and Electronic Materials, Australian Institute for Innovative Materials, University of Wollongong, North Wollongong, NSW 2522, Australia.
authors: Shixue
authors: S
authors: Dou
authors: Department of Physics, Banaras Hindu University, Varanasi-221005, India.
authors: O N
authors: ON
authors: Srivastava
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