Bulk copper (Ⅱ) oxide (CuO), heat treated at 1223 K, shows extraordinarily high dielectric constant (ε_r ～ 10~4), almost independent of temperature (above 230 K) and frequency in the kilohertz region. A sudden decrease of ε_r is observed at lower temperature (below 150 K). X-ray photoelectron spectroscopy and high resolution transmission electron microscopy studies confirm the presence of a microscopic amount of Cu~(3+) in annealed CuO. The dielectric behavior of CuO can be explained by Maxwell-Wagner-type polarization mechanism and thermally activated mechanism.
展开▼
