Intrinsic strain effect on critical current and its reversibility for YBCO coated conductors with different buffer layers

TLDR

Quenching occurs near the Hastelloy substrate’s yield strain. The study examined the uniaxial strain dependence of critical current in YBCO coated conductors on Hastelloy substrates with IBAD‑CeO₂/YSZ or ISD‑MgO buffer layers. Critical current rose with strain, reached a maximum, then fell; the reversible strain region and its limit vary with buffer layer, with CeO₂/YSZ tapes recovering after 0.30% strain while MgO tapes irreversibly degrade below 0.22%, and the normalized Ic versus intrinsic strain follows a unified scaling function.

Abstract

The uniaxial strain dependence of the critical current was examined for YBCO coated conductors with IBAD-CeO2/YSZ or ISD-MgO buffer layers on Hastelloy substrates. Ic increased with increasing applied strain, reached a maximum and decreased for higher strain values. The reversible strain region of Ic variation was observed. The reversible strain limit depends on the buffer layers. For the CeO2/YSZ buffered tape, Ic recovered the initial value even after the applied strain reached 0.30%. On the other hand, an irreversible degradation of Ic was observed at the strain less than 0.22% for the MgO buffered tape. The overall relationship between the Ic normalized by the peak value and the intrinsic strain in YBCO obeyed a unified scaling function. Quenching occurred at the strain close to the yield strain of the Hastelloy substrate.