Superconducting transitions were measured in field-cooled cooling and field-cooled warming modes in external magnetic fields ranging between 1 mT and 7 T on YBa2Cu3Ox (Y123) single crystals with and without the fishtail effect. The Y123 crystal with the fishtail effect exhibited a two-step transition when being cooled in high fields, while the Y123 crystal without the fishtail showed a single step transition. Furthermore, an upturn in magnetic moment was observed at lower temperatures for Y123 with the fishtail effect. Such an upturn is ascribed to the local Cu magnetic moment due to oxygen vacancies. The fishtail effect is thus caused by oxygen vacancies.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Physics and Astronomy (miscellaneous)
- Condensed Matter Physics