High temperature superconductors in the systems YBa2Cu3O7-δ (123) and decomposed YBa2Cu4O7-δ (124) often contain planar faults with (001) as the nominal fault plane. Such planar defects have been analyzed using a unique combination of high resolution TEM (HRTEM) imaging and high resolution analytical electron microscopy (HRAEM). HRTEM confirmed that these planar faults are stacking faults with double or multiple insertion of crystal planes parallel to the c-plane of the crystal, most probably CuO planes. X-ray microanalysis clearly showed enrichment of copper associated with these defects. EELS fine structure of CuL23 edge from the fault regions resembled that of pure CuO. The combined results indicate that the planar defects are in fact insertions of extra CuO planes in an otherwise regular 123 crystal unit cell.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering