Strain Has Major Effect on High-Temp Superconductors

Magneto-optical image of magnetic fields within a YBCO superconductor showing electrically connected grains (yellow) and grain boundaries (green) that form barriers to superconducting currents. The large reversible effect of strain observed by NIST might be due to associated changes in grain boundaries, which raise the barriers to current flow and lower the material's current-carrying capability. Credit: D.C. van der Laan/NIST