Laser drilling: Enhancing superconducting joint of GdBa2Cu 3O7-δ coated conductors

Y. J. Park, M. W. Lee, Y. K. Oh, H. G. Lee

Research output: Contribution to journalArticlepeer-review

47 Citations (Scopus)

Abstract

While GdBa2Cu3O7-δ (GdBCO) coated conductors (CCs) have been proposed for superconducting applications, they have not been used in devices with persistent current mode (PCM) operation because of a lack of joining techniques. A superconducting joint of CCs, formed via melting diffusion and oxygenation annealing, offers no electrical resistance between the CCs, thus establishing a superconducting closed loop for PCM operation. Because superconductivity degrades with oxygen out-diffusion during melting diffusion, oxygenation annealing allows oxygen diffusion into the GdBCO lattices. As effective oxygenation annealing requires oxygen pathways in the joint, low solubility and diffusivity of oxygen in the buffer and CC substrate hinder full superconductivity recovery. Here we show a laser-drilling technique to produce microholes as conduits on the surfaces of GdBCO CCs' to promote oxygen in-diffusion, which resulted in reduced superconductivity recovery time. Superconductivity was fully recovered after laser drilling, melting diffusion at 850 °C for 1 min, and oxygenation annealing at 500 °C for 350 h.

Original languageEnglish
Article number085008
JournalSuperconductor Science and Technology
Volume27
Issue number8
DOIs
Publication statusPublished - 2014 Aug 1

Keywords

  • GdBCO coated conductors
  • laser drilling
  • oxygen pathways
  • persistent current mode operation
  • superconducting joint

ASJC Scopus subject areas

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

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