Large intrinsic effect of axial strain on the critical current of high-temperature superconductors for electric power applications

Abstract

A remarkably large reversible reduction in the critical current of "second generation" high-temperature superconductors for electric power applications has been measured with a new technique over a wide range of mechanical strain. The effect amounts to a 40% reduction in critical current at 1% compressive strain in self-magnetic field, and is symmetric for compressive and tensile strains. The intrinsic effect is measured in highly aligned multigranular YBa 2 Cu 3 O 7−d coated conductors made by different processes, including superconductors with nanoscale pinning centers. This effect and its magnitude are expected to have a significant impact on power applications and provide a useful new parameter for probing the fundamental nature of current transport in high-temperature superconductors.

Strain Distribution in REBCO-Coated Conductors Bent With the Constant-Perimeter Geometry

“…The irreversible tensile strain limit, beyond which the conductor I c permanently degrades, ranges from 0.4% to 0.7% for recent commercial conductors with Hastelloy substrates [16,[22][23][24]. For the compressive axial strain, a large intrinsic and reversible effect on conductor I c has been observed [25]. An axial compressive strain between 0.5% and 1.0% can reduce the conductor I c for 20% [23,26,27].…”

Robustness of two-dimensional topological insulator states in bilayer bismuth against strain and electrical field

“…In fact, strain and interfacial engineering have now become a common strategy to tailor a wide range of thin film properties, from crystalline structure, 1 growth morphology (especially nanoscale assembly), 2 electronic band structure, 3 magnetism, 4 carrier mobility, 5 to superconductivity. 6 Recently, a new class of materials of topological insulators (TIs) has been discovered.…”

Measurements on Subscale Y-Ba-Cu-O Racetrack Coils at 77 K and Self-Field

“…Given the Hastelloy modulus of 195 GPa at room temperature [17], 30 MPa yields a tensile strain of 0.02%, which is below the critical applied axial strain in the specification [18] as well as other published results [19], [20]. In addition, the YBCO side of the conductor faces the pole-island during the winding so that the YBCO layer is under compression to cancel at least part of the hoop stress when the coil is energized.…”