DIELECTRIC-PROPERTIES OF GD2CUO4

The complex dielectric response of the Gd2CuO4 samples measured from 2 0 Hz to 1 MHz and from 20 K to 300 K reveals very high real part of th e dielectric constant epsilon' > 10(4) at 300 K and > 5 X 10(3) above 200 K. The large polarizability results from a thermally activated pro cess with a very small activation energy of 0.065 eV and extra additio nal polarization. We observed one frequency-dependent and one frequenc y-independent peak in dissipation factor D(T,omega) curves and corresp onding features in imaginary part of the dielectric constant epsilon'' curves. The first peak occurs at T similar to 230 K and is thought to be due to the occurrence of antiferromagnetic transition in the sampl e and the second one occurs over the range of 50 to 120 K and is relat ed to the change of conductivity mechanism. (C) 1998 Elsevier Science B.V.