Properties of YBa2Cu3O7−δ thick films on flexible buffered metallic substrates

TLDR

The study reports the superconducting and mechanical properties of YBa₂Cu₃O₇₋δ thick films on Ni‑based alloys with a textured YSZ buffer layer. The YBCO and YSZ layers were deposited by pulsed laser deposition and ion beam assisted deposition, respectively. The films exhibit critical current densities exceeding 1×10⁶ A/cm² at 75 K (≈1×10⁷ A/cm² at 4 K), zero‑field currents of 120 A in a 2‑µm film, angular‑dependent peaks indicating additional pinning from grain/twin boundaries, and bending tests at 75 K show strain tolerance of 0.4 % (tension) and >1 % (compression).

Abstract

We report superconducting and mechanical properties of YBa2Cu3O7−δ (YBCO) thick films on Ni-based alloys with a textured yttria-stabilized zirconia (YSZ) buffer layer. The YBCO and YSZ layers were deposited by pulsed laser deposition and ion beam assisted deposition, respectively. It was found that the transport critical current density (Jc) correlates very well with the YBCO mosaic spread. Jc over 1×10 6 A/cm2 at 75 K and ∼1×107 A/cm2 at 4 K were obtained in the 1-μm thick YBCO films. Zero field critical current of 120 amps at 75 K was obtained in a 2-μm-thick and 1-cm-wide YBCO film. Angular dependence measurement revealed Jc peaks for both H∥c and H∥a-b. The peak for H∥c implies additional pinning due to defects such as small angle grain boundaries or twin boundaries. Bending tests at 75 K showed that the YBCO thick films on the metallic substrates could sustain a strain of 0.4% and over 1% for tension and compression, respectively.