Copper (II) oxide as a giant dielectric material

Bulk copper (II) oxide (CuO), heat treated at 1223 K, shows extraordinarily high dielectric constant (epsilon(r)similar to 10(4)), almost independent of temperature (above 230 K) and frequency in the kilohertz region. A sudden decrease of epsilon(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 Cu3+ in annealed CuO. The dielectric behavior of CuO can be explained by Maxwell-Wagner-type polarization mechanism and thermally activated mechanism. (c) 2006 American Institute of Physics.