Large static dielectric constant in the high-temperature phase of polycrystalline YBa_{2}Cu_{3}O_{x}

Abstract

A large and strongly temperature-dependent static dielectric constant \ensuremath{\kappa} is found in the high-temperature (T>900 \ifmmode^\circ\else\textdegree\fi{}C) phase of ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{\mathrm{x}}$. Values of \ensuremath{\kappa} from \ensuremath{\sim}30 at 4.3 K to \ensuremath{\sim}700 at 290 K have been measured in samples quenched from 950 \ifmmode^\circ\else\textdegree\fi{}. Some consequences of the ferroelectriclike polarizability in the phase which precedes the metallic/superconducting phase are noted.