Abstract

The effect of α-particle irradiation on a NdFeAs(O,F) thin film has been investigated to determine how the introduction of defects affects basic superconducting properties, including the critical temperature T c and the upper critical field H c2, and properties more of interest for applications, like the critical current density J c and the related pinning landscape. The irradiation-induced suppression of the film T c is significantly smaller than on a similarly damaged single crystal. Moreover H c2 behaves differently, depending on the field orientation: for H//c the H c2 slope monotonically increases with increasing disorder, whereas for H//ab it remains constant at low dose and it increases only when the sample is highly disordered. This suggests that a much higher damage level is necessary to drive the NdFeAs(O,F) thin film into the dirty limit. Despite the increase in the low temperature H c2, the effects on the J c(H//c) performances are moderate in the measured temperature and field ranges, with a shifting of the pinning force maximum from 4.5 to 6 T after an irradiation of 2 1015 cm-2. On the contrary, J c(H//ab) is always suppressed. The analysis demonstrates that irradiation does introduce point defects (PD) acting as pinning centres proportionally to the irradiation fluence but also suppresses the effectiveness of c-axis correlated pinning present in the pristine sample. We estimate that significant performance improvements may be possible at high field or at temperatures below 10 K. The suppression of the J c(H//ab) performance is not related to a decrease of the J c anisotropy as found in other superconductors. Instead it is due to the presence of PD that decrease the efficiency of the ab-plane intrinsic pinning typical of materials with a layered structure.

Original languageEnglish (US)
Article number034002
JournalSuperconductor Science and Technology
Volume31
Issue number3
DOIs
StatePublished - Feb 5 2018

Keywords

  • critical current
  • Fe-based superconductors
  • irradiation, pinning properties
  • NdFeAs(O,F)

ASJC Scopus subject areas

  • Ceramics and Composites
  • Condensed Matter Physics
  • Metals and Alloys
  • Electrical and Electronic Engineering
  • Materials Chemistry

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  • Cite this

    Tarantini, C., Iida, K., Sumiya, N., Chihara, M., Hatano, T., Ikuta, H., Singh, R., Newman, N., & Larbalestier, D. C. (2018). Effect of α-particle irradiation on a NdFeAs(O,F) thin film. Superconductor Science and Technology, 31(3), [034002]. https://doi.org/10.1088/1361-6668/aaa821