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