We attempted to control the volume fraction of the in-plane domains of <i>RE</i>Ba<sub>2</sub>Cu<sub>3</sub>O<sub>7<i></i></sub> coated conductors (<i>RE</i>BCO-CCs) by annealing under a bending strain applied at high temperature. We succeeded in changing the volume fraction of the region where the <i>a</i> axis of <i>RE</i>BCO aligns along the longitudinal direction of <i>RE</i>BCO-CC, <i>f</i><sub>A</sub>, up to 90% when a compressive bending strain of 1.35% is applied along the longitudinal direction. We found that <i>f</i><sub>A</sub> evaluated by repeated X-ray diffraction measurements decreases over time if the domain-controlled <i>RE</i>BCO-CCs with a high <i>f</i><sub>A</sub> value is kept flat, whereas <i>f</i><sub>A</sub> remains high if the sample remains bent. In addition, we also observed that <i>f</i><sub>A</sub> in the as-received sample increases over time if the sample is exposed to a compressive bending strain at room temperature. These results suggest that oxygen atoms can migrate in <i>RE</i>BCO even at room temperature when a uniaxial strain is applied to the <i>RE</i>BCO-CC. Such a temporal variation of <i>f</i><sub>A</sub> probably leads to changes in the superconducting properties, and may become important for the design of <i>RE</i>BCO pancake coils.
- High-temperature superconductors
- Superconducting films
- X-ray diffraction
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering