Axial strain dependence at 77 K of the critical current of thick YBaCuO films on Ni-alloy substrates with IBAD buffer layers

Abstract

The strain sensitivity of YBCO coated conductors has been investigated by measuring the critical current density J/sub c/ in self field at 77K, as a function of applied tensile strain. The YBCO coated conductor used an Inconel substrate. One side was coated with a biaxially textured YSZ buffer layer, using ion-beam-assisted-deposition (IBAD), and was subsequently coated with a 2.5 micron thick YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// layer by pulsed laser deposition (PLD). The superconductor was then coated with a silver cap layer. For the I/sub c/-strain measurements 78 mm long sections were cut from a 115 cm long length. This was previously produced to demonstrate the feasibility of long YBCO coated conductors using the IBAD process. At 77K up to 0.5% strain does not change J/sub c/ by more than 3% This strain dependence is better than the tensile stress dependence of J/sub c/ when samples are bent at room temperature.