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

The strain sensitivity of YBCO coated conductors has been investigated by measuring the critical current density J(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 YBa2Cu3O7-delta layer by Pulsed Laser Deposition (PLD), The superconductor was then coated with a silver cap layer. For the I-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 er conductors using the IBAD process. At 77K up to 0.5% strain does not change J(c) by more than 3%. This strain dependence is better than the tensile stress dependence of J(c) when samples are bent at room temperature.