Ferroelectric Relaxor Behavior and Dielectric Relaxation in Strontium Barium Niobate – A Lead-Free Relaxor Ceramic Material

Anamika Dwivedi1

K. N. Singh2,Email

Milan Hait3,Email

P. K. Bajpai4

1Department of Physics, YBN University, Ranchi, Jharkhand- 834010, India.
2Department of Physics, OP Jindal University, Punjipathara Raigarh C.G. - 496109, India.
3Department of Chemistry, Dr. C. V. Raman University, Bilaspur C.G.-495113, India.
4Advance Research Laboratory, Department of Pure & Applied Physics, GGV, Bilaspur C.G.-495 009, India.

 

Abstract

Various compositions of single-phase ceramics of Strontium barium niobate, SrxBa1-xNb2O6 (x=0.25, 0.50 abbreviated as SBN25 and SBN50) have been synthesized by standard solid-state reaction route by a precise control of cooling rate and optimizing the sintering temperatures. Material calcined at 1250oC and sintered at 1300oC is stabilized in pure phase with a tetragonal structure having density >95%. Lattice parameters for SBN25 (a= 12.467(4) Å, c=3.956(5) Å), and SBN50 (a= 12.435(2) Å, c= 3.945(7) Å). Both compositions show a relaxor type behavior with a diffuse phase transition. Modified Curie-Weiss law is used to fit the dielectric data. The dielectric relaxation obeys the Vogel–Fulcher relationship with a freezing temperature of 277.3K for SBN25 and 278.4K for SBN50. Significant dielectric dispersion is observed in the low frequency regime in both components of dielectric permittivity and a small dielectric relaxation peak is observed. This is associated with the defect related hopping process. The value of tilt parameter (α) in Cole-Cole analysis varies from 0.12 to 0.17 for SBN25 and 0.13 to 0.21 for SBN50 with increasing the temperature from 75oC to 150oC, indicates poly-dispersive nature of the dielectric relaxation. This material can be a good candidate for hologram and electro-optic data storage media.

Ferroelectric Relaxor Behavior and Dielectric Relaxation in Strontium Barium Niobate – A Lead-Free Relaxor Ceramic Material