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Ultra-high critical current densities of superconducting YBa 2Cu 3O 7-δ thin films in the overdoped state. Sci Rep 2021; 11:8176. [PMID: 33854183 PMCID: PMC8047038 DOI: 10.1038/s41598-021-87639-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 03/24/2021] [Indexed: 02/02/2023] Open
Abstract
The functional properties of cuprates are strongly determined by the doping state and carrier density. We present an oxygen doping study of YBa2Cu3O7-δ (YBCO) thin films from underdoped to overdoped state, correlating the measured charge carrier density, [Formula: see text], the hole doping, p, and the critical current density, [Formula: see text]. Our results show experimental demonstration of strong increase of [Formula: see text] with [Formula: see text], up to Quantum Critical Point (QCP), due to an increase of the superconducting condensation energy. The ultra-high [Formula: see text] achieved, 90 MA cm-2 at 5 K corresponds to about a fifth of the depairing current, i.e. a value among the highest ever reported in YBCO films. The overdoped regime is confirmed by a sudden increase of [Formula: see text], associated to the reconstruction of the Fermi-surface at the QCP. Overdoping YBCO opens a promising route to extend the current carrying capabilities of rare-earth barium copper oxide (REBCO) coated conductors for applications.
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He X, Wen Y, Zhang C, Lai Z, Chudnovsky EM, Zhang X. Enhancement of critical current density in a superconducting NbSe 2 step junction. NANOSCALE 2020; 12:12076-12082. [PMID: 32478360 DOI: 10.1039/d0nr03902k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We investigate the transport properties of a NbSe2 nanodevice consisting of a thin region, a thick region and a step junction. The superconducting critical current density of each region of the nanodevice has been studied as a function of temperature and magnetic field. We find that the critical current density has similar values for both the thin and thick regions away from the junction, while the critical current density of the thin region of the junction increases to approximately 1.8 times as compared with the values obtained for the other regions. We attribute such an enhancement of critical current density to the vortex pinning at the surface step. Our study verifies the enhancement of the critical current density by the geometrical-type pinning and sheds light on the application of 2D superconductors.
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Affiliation(s)
- Xin He
- Physical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.
| | - Yan Wen
- Physical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.
| | - Chenhui Zhang
- Physical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.
| | - Zhiping Lai
- Physical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.
| | - Eugene M Chudnovsky
- Physics Department, Lehman College and Graduate School, The City University of New York, 250 Bedford Park Boulevard West, Bronx, New York 10468-1589, USA.
| | - Xixiang Zhang
- Physical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.
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Pushing the limits for the highest critical currents in superconductors. Proc Natl Acad Sci U S A 2019; 116:10201-10203. [PMID: 31085652 PMCID: PMC6534980 DOI: 10.1073/pnas.1905568116] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Kimmel GJ, Glatz A, Vinokur VM, Sadovskyy IA. Edge effect pinning in mesoscopic superconducting strips with non-uniform distribution of defects. Sci Rep 2019; 9:211. [PMID: 30659219 PMCID: PMC6338761 DOI: 10.1038/s41598-018-36285-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 11/15/2018] [Indexed: 12/04/2022] Open
Abstract
Transport characteristics of nano-sized superconducting strips and bridges are determined by an intricate interplay of surface and bulk pinning. In the limiting case of a very narrow bridge, the critical current is mostly defined by its surface barrier, while in the opposite case of very wide strips it is dominated by its bulk pinning properties. Here we present a detailed study of the intermediate regime, where the critical current is determined, both, by randomly placed pinning centres and by the Bean-Livingston barrier at the edge of the superconducting strip in an external magnetic field. We use the time-dependent Ginzburg-Landau equations to describe the vortex dynamics and current distribution in the critical regime. Our studies reveal that while the bulk defects arrest vortex motion away from the edges, defects in their close vicinity promote vortex penetration, thus suppressing the critical current. We determine the spatial distribution of the defects optimizing the critical current and find that it is in general non-uniform and asymmetric: the barrier at the vortex-exit edge influence the critical current much stronger than the vortex-entrance edge. Furthermore, this optimized defect distribution has a more than 30% higher critical current density than a homogeneously disorder superconducting film.
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Affiliation(s)
- Gregory J Kimmel
- Materials Science Division, Argonne National Laboratory, 9700 S Cass Av, Lemont, IL, 60439, USA
- Department of Engineering Sciences and Applied Mathematics, Northwestern University, 633 Clark St, Evanston, IL, 60208, USA
| | - Andreas Glatz
- Materials Science Division, Argonne National Laboratory, 9700 S Cass Av, Lemont, IL, 60439, USA.
- Department of Physics, Northern Illinois University, DeKalb, IL, 60115, USA.
| | - Valerii M Vinokur
- Materials Science Division, Argonne National Laboratory, 9700 S Cass Av, Lemont, IL, 60439, USA
| | - Ivan A Sadovskyy
- Materials Science Division, Argonne National Laboratory, 9700 S Cass Av, Lemont, IL, 60439, USA
- Computation Institute, University of Chicago, 5735 S Ellis Av, Chicago, IL, 60637, USA
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