Although we can use misorientation angle to distinguish the grain boundaries that can carry high critical current density in high temperature superconductors (HTS) from those that cannot, there is no established normal state property equivalent. In this paper, we explore the superconducting and normal state properties of the grains and grain boundaries of polycrystalline YBa2Cu3O7−x (YBCO) using complementary magnetisation and transport measurements, and calculate how resistive grain boundaries must be to limit in polycrystalline superconductors. The average resistivity of the grain boundaries, in our micro- and nanocrystalline YBCO are 0.12 Ωm and 8.2 Ωm, values which are much higher than that of the grains and leads to huge values of 2 × 103 and 1.6 × 105 respectively. We find that the grain boundaries in our polycrystalline YBCO are sufficiently resistive that we can expect the transport to be several tens of orders of magnitude below the potential current density of the grains in our YBCO samples, as is found experimentally. Calculations presented show that increasing values by ∼2 orders of magnitude in high fields is still possible in all state-of-the-art technological high-field superconductors. We conclude: grain boundary engineering is unlikely to improve sufficiently in randomly aligned polycrystalline YBCO, to make it technologically useful for high-field applications; in low temperature superconducting intermetallics, such as Nb3Sn, large increases in may be achieved by completely removing the grain boundaries from these materials and, as is the case for thin films of Nb, Ba(FeCo)2As2 and HTS materials, by incorporating additional artificial pinning.
Publisher's copyright statement:Original content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Manuscript version: Accepted Manuscript Accepted Manuscript is "the version of the article accepted for publication including all changes made as a result of the peer review process, and which may also include the addition to the article by IOP Publishing of a header, an article ID, a cover sheet and/or an 'Accepted Manuscript' watermark, but excluding any other editing, typesetting or other changes made by IOP Publishing and/or its licensors"This Accepted Manuscript is © 2017 IOP Publishing Ltd.As the Version of Record of this article is going to be / has been published on a gold open access basis under a CC BY 3.0 licence, this Accepted Manuscript is available for reuse under a CC BY 3.0 licence immediately.Everyone is permitted to use all or part of the original content in this article, provided that they adhere to all the terms of the licence https://creativecommons.org/licences/by/3.0Although reasonable endeavours have been taken to obtain all necessary permissions from third parties to include their copyrighted content within this article, their full citation and copyright line may not be present in this Accepted Manuscript version. Before using any content from this article, please refer to the Version of Record on IOPscience once published for full citation and copyright details, as permissions may be required. All third party content is fully copyright protected and is not published on a gold open access basis under a CC BY licence, unless that is specifically stated in the figure caption in the Version of Record.View the article online for updates and enhancements. AbstractThe detrimental effects of grain boundaries have long been considered responsible for the low critical current densities ( c ) in high temperature superconductors. In this paper, we apply the quantitative approach used to identify the cause of the 'weak-link' grain boundary behaviour in YBa2Cu3O7 [1], to the Bi2Sr2CaCu2O8 and Bi2Sr2Ca2Cu3O10 materials that we have fabricated. Magnetic and transport measurements are used to characterise the grain and grain boundary properties of micro-and nanocrystalline material. Magnetisation measurements on all nanocrystalline materials show non-Bean-like behaviour and are consistent with sur...
Rare earth (RE) elements are promising to improve the property of catalysts due to their distinctive 4 f electron orbital. Herein, a heterogeneous material of FeÀ NiS nanorods encapsulated in Ce-doped NiO x with 3D core-shell structure (FeÀ NiS@NiCeO x ) was constructed on carbon cloth (CC) through a straightforward solvothermal reaction and a subsequent electrodeposition for enhancing the electrocatalytic performance towards oxygen evolution reaction (OER) in alkaline medium. The strategy facilitates a synergy among the components, including an enlarged electrochemical active area of FeÀ NiS by the involvement of Fe and an ameliorated durability of FeÀ NiS nanorod by encapsulated in NiCeO x shell. Furthermore, a flexible valence alternation between Ce (III) and Ce (IV) speeds up the charges transfer between Ni(II) and Ni(III). In 1.0 mol L À 1 KOH, the FeÀ NiS@NiCeO x /CC electrode shows the lowest overpotential of 230 mV to achieve the current density of 50 mA cm À 2 , the smallest Tafel slope of 63 mV dec À 1 and a superior durability with only a potential fluctuation of 0.01 V on a chronopotentiometry curve within 24 h. Further research suggests that FeÀ NiS@NiCeO x /CC exhibits the best performance of the three as-fabricated FeÀ NiS@NiREO x /CC (RE = Ce, La, Pr) catalysts.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.