Dielectric relaxor and conductivity characteristics of undoped and samarium doped barium bismuth niobate ferroelectric ceramics

ABSTRACT

The polycrystalline BaBi₂Nb₂O₉ and Ba(Bi_0.9Sm_0.1)₂Nb₂O₉ ceramics have been fabricated via the molten salt synthesis route. The temperature dependence of dielectric and electrical conductivity properties of BBN and BBSmN ceramics investigated at various frequencies have revealed the characteristic features of relaxor behaviour. The incorporation of Sm³⁺ for Bi³⁺ has induced a downward shift in the dielectric maximum temperature (165°C–120°C) with the decrease in dielectric constant maximum (372 – 212) at 100 kHz. The estimated degree of diffuseness (γ) was found to be 2.17 for BBN and 1.93 for BBSmN ceramic samples. The activation energy obtained from the Arrhenius plot revealed the existence of motion of oxygen ion vacancy in these ceramics.

KEYWORDS:

• Barium bismuth samarium niobate
• relaxor ferroelectrics
• electrical conductivity

Acknowledgments

The authors thank Alagappa University, Karaikudi, India and Karunya University, Coimbatore, India for their assistance in characterization. This work was supported by Department of Science and Technology (Project No: SR/FT/CS-065/2009), India.