High-temperature dielectric properties of Gd2O3-doped CeO2 ceramics

• Samples of Gd2O3-doped CeO2 ceramics were fabricated by the co-precipitation method.
• Three thermally activated dielectric relaxations were observed.
• The relaxations are related to the bulk, grain boundary and contact effect.

Ceramic samples of Gd2O3-doped CeO2 (GDC) were fabricated by the co-precipitation method. The dielectric properties were investigated as functions of temperature (350–950 K) and frequency (100 Hz to 10 MHz). Three relaxations with the activation energies of 0.76, 0.88, and 1.03 eV in the order of ascending temperature were observed in GDC. The low-, middle-, and high-temperature relaxations are argued to be related to the bulk response caused by the Gd dopant-oxygen vacancy pairs, grain boundary, and contact effects, respectively.