Conductivity relaxation in NiTiO3 at high temperatures

• NiTiO3 shows intrinsic dielectric response in the temperature range below 400 K.
• The two relaxations are related to conductivity relaxation.
• Oxygen vacancies from singly to doubly charged states are around 700 K in NiTiO3.

NiTiO3 ceramics were prepared via the traditional solid-state reaction route. The dielectric properties of NiTiO3 ceramics have been systematically investigated in the temperature range from room temperature to 1073 K NiTiO3 ceramics exhibit intrinsic dielectric response in the temperature range below 400 K. Two relaxations were observed in the temperature range higher than 400 K. The relaxation activation energy is 0.95 eV and 1.17 eV for the low- and high-temperature relaxations, respectively. Our results strongly indicate that the two relaxations are related to conductivity relaxation associated with the singly and doubly ionized oxygen vacancies.