Dielectric relaxation in layer-structured SrBi2−xGdxNb2O9 (x = 0.0, 0.4, 0.6, and 0.8) lead-free ceramics

The gadolinium (Gd 3+ )-doped SrBi 2 Nb 2 O 9 (SBN) ceramics with the chemical formula SrBi 2 − x Gd x Nb 2 O 9 ( x  = 0.0, 0.4, 0.6, and 0.8) have been prepared through traditional solid-state sintering method. X-ray diffraction reveals a single-phase-layered perovskite structure for all compositio...

Full description

Saved in:
Bibliographic Details
Published in:Journal of materials science. Materials in electronics 2022-06, Vol.33 (16), p.12997-13011
Main Authors: Nagamani, S., Nitchal Kiran, J., Siva Basivi Reddy, B., Nageswara Rao, B., Anindhya Kiran, J., Sambasiva Rao, K.
Format: Article
Language:English
Subjects:
Bismuth compounds
Ceramics
Characterization and Evaluation of Materials
Chemistry and Materials Science
Composition
Dielectric loss
Dielectric properties
Dielectric relaxation
Ferroelectric materials
Ferroelectricity
Frequency ranges
Gadolinium
Lead free
Materials Science
Optical and Electronic Materials
Perovskite structure
Perovskites
Phase transitions
Relaxors
Room temperature
Transition temperature
Unit cell
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The gadolinium (Gd 3+ )-doped SrBi 2 Nb 2 O 9 (SBN) ceramics with the chemical formula SrBi 2 − x Gd x Nb 2 O 9 ( x  = 0.0, 0.4, 0.6, and 0.8) have been prepared through traditional solid-state sintering method. X-ray diffraction reveals a single-phase-layered perovskite structure for all compositions with shrinkage of the unit cell of SBN. The plate-like morphology revealed from SEM is symbolic of the characteristic Aurivillius phase of ceramics. Shifting of Raman phonon modes indicates the reduced rattling space of NbO 6 octahedral with an increase in Gd concentration. The dielectric properties of all compositions are studied as a function of temperature (RT—500 °C) over the frequency range (50 Hz to 1 MHz). Softening the lowest frequency mode with increasing x in SBGN shows the transition from ferroelectric to paraelectric at room temperature (RT). The flattening of dielectric permittivity and low dielectric loss is observed in SBN and gadolinium-modified SBN (SBGN) ceramic samples at RT. The phase transition becomes diffused and transition temperature gets shifted from 430 to 330 °C with an increase in gadolinium concentration at higher frequencies. The increase in broadness with an increase in frequency suggests that the presentation materials are of ferroelectric relaxor type. The degree of relaxor behavior (γ) increases from 1.05 for x  = 0.0 to 1.57 for x  = 0.8. The relaxor behavior along with diffuseness was noticed in the fabricated ceramics.
ISSN:0957-4522
1573-482X
DOI:10.1007/s10854-022-08241-6