Effects of proton irradiation on flux-pinning properties of underdoped Ba(Fe0.96Co0.04)2As2 pnictide superconductor

JOURNAL OF ALLOYS AND COMPOUNDS

卷:694

Article

Salem-Sugui, S., Jr.¹  Moseley, D.²  Stuard, S. J.¹  Alvarenga, A. D.³  Sefat, A. S.⁴  Cohen, L. F.²  Ghivelder, L.¹ 

[1] Univ Fed Rio de Janeiro, Inst Fis, BR-21941972 Rio De Janeiro, RJ, Brazil

[2] Imperial Coll London, Blackett Lab, London SW7 2AZ, England

[3] Inst Nacl Metrol Qualidade & Tecnol, BR-25250020 Duque De Caxias, RJ, Brazil

[4] Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA

关键词: Pnictides;    Proton irradiation;    Superconducting critical current;    Flux-pinning;   

DOI  :  10.1016/j.jallcom.2016.10.103

来源: Elsevier

【 摘 要 】

We study the effect of proton irradiation on Ba(Fe0.96Co0.04)(2)As-2 superconducting single crystals from combined magnetisation and magnetoresistivity measurements. The study allows the extraction of the values of the apparent pinning energy U-0 of the samples prior to and after irradiation, as well as comparison of the values of U-0 obtained from the flux-flow reversible region with those from the flux-creep irreversible region. Irradiation reduces T-c modestly, but significantly reduces U-0 in both regimes: the critical current density J(c) is modified, most strikingly by the disappearance of the second magnetisation peak after irradiation. Analysis of the functional form of the pinning force and of the temperature dependence of J(c) for zero field, indicates that proton irradiation in this case has not changed the pinning regime, but has introduced a high density of shallow point-like defects. By considering a model that takes into account the effect of disorder on the irreversibility line, the data suggests that irradiation produced a considerable reduction in the average effective disorder overall, consistent with the changes observed in U-0 and J(c). (C) 2016 Elsevier B.V. All rights reserved.

【 授权许可】

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