Domainlike defects observed in the high-temperature superconductor Y-Ba-Cu-O

Abstract

Transmission-electron microscopy of the high-superconductivity-transition-temperature oxide ${\mathrm{Y}}_{1}{\mathrm{Ba}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{x}$ reveals the presence of planar defects along [110] direction more-or-less uniformly spaced (spacing \ensuremath{\sim}300 \AA{}) and dispersed throughout the specimens. These defects persisted on cooling down to the transition temperature (93 K), but disappeared on heating above 400\ifmmode^\circ\else\textdegree\fi{}C in in situ experiments inside the electron microscope. The possible role of these "domains" or interfaces in superconductivity is discussed.