Dielectric and pyroelectric response in Nb/semiconducting Y-Ba-Cu-O/Nb structures

A study on the dielectric and pyroelectric properties of nonmetallic, polycrystalline Y-BaCu-O thin films was performed for a range of temperatures (170-360K) and frequencies (2Hz-1kHz). The complex permittivity, as a function of frequency, relaxed according to a first-order Debye Model. This relaxation was shown to be thermally activated, with an activation energy equal to the activation energy for the de conduction of the material. The behavior of the data indicates that the polarization source is localized carriers near the Fermi level. Pyroelectricity was measured over a temperature range of 170 - 290 K, showing a constant response over these temperatures. Moreover, the pyroelectric properties of YBCO exhibited a strong sensitivity to poling at elevated temperatures, with a dramatic increase in,the magnitude of the response. The pyroelectric coefficient changed from p approximate to 400 nC/(cm(2)-K) for the unpoled case to p approximate to 20 mu C/(cm(2)-K) after poling with 5000 V/cm for one hour at 320 K.