Dielectric properties of Gd₂CuO₄

The complex dielectric response of the Gd₂CuO₄ samples measured from 20 Hz to 1 MHz and from 20 K to 300 K reveals very high real part of the dielectric constant ε′ > 10⁴ at 300 K and > 5 × 10³ above 200 K. The large polarizability results from a thermally activated process with a very small activation energy of 0.065 eV and extra additional polarization. We observed one frequency-dependent and one frequency-independent peak in dissipation factor D(T, ω) curves and corresponding features in imaginary part of the dielectric constant ε″ curves. The first peak occurs at T ∼ 230 K and is thought to be due to the occurrence of antiferromagnetic transition in the sample and the second one occurs over the range of 50 to 120 K and is related to the change of conductivity mechanism.