Influence of Nb ion doping on the electrical properties of nanocrystalline NiTiO3 ceramics and their universal behavior

摘要

Pure and Nb ion-doped NiTiO3 (Nb:NiTiO3) were prepared in nanostructured form by sol-gel method with Nb ion concentration varying from 1 to 20 mol%. They were obtained in rhombohedral crystal structure with an average particle size varying from 28 to 35 nm. Shift to lower Bragg angle hinted the proper doping of Nb ions in the host cationic site. Electrical properties of Nb:NiTiO3 were studied by impedance spectroscopy in the temperature range from 550 to 700 degrees C, and they showed a non-Debye type of relaxation. Less than 1 of beta value by KWW fit also showed the same. Its conductivity followed an Arrhenius behavior with the activation energy varies from 1.04 to 1.12 eV that was attributed to the migration of oxygen ions that are the conduction species in Nb:NiTiO3. Universal scaling behavior shown by Nb:NiTiO3 implied that the mechanism for dielectric relaxation is independent of temperature and Nb ion content.