New Piezoceramic SrBi₂Nb_2-2WSnO₉: Crystal Structure, Microstructure and Dielectric Properties

Area of Science:

• Materials Science
• Solid-State Chemistry
• Ceramics Engineering

Background:

• Aurivillius-Smolensky phases (ASPs) are known for their unique structural and electrical properties.
• Strontium bismuth niobate (SrBi2Nb2O9) is a key material in this class, but its properties can be further optimized.
• Previous research suggested limitations in using tin (Sn) as a dopant in such materials.

Purpose of the Study:

• To synthesize and characterize a new piezoceramic compound, SrBi2Nb2-2xWxSnxO9.
• To investigate the effect of co-doping with tin (Sn) and tungsten (W) on the structural and electrophysical properties of SrBi2Nb2O9.
• To challenge the existing notion regarding the ineffectiveness of tin as a doping element in these materials.

Main Methods:

• High-temperature solid-phase reaction for synthesis.
• X-ray diffraction (XRD) for structural analysis and phase identification.
• Dielectric spectroscopy to measure relative permittivity (ε/ε0) and dielectric loss tangent (tan δ) at various frequencies and temperatures.

Main Results:

• Successfully synthesized single-phase and two-phase SrBi2Nb2-2xWxSnxO9 (x = 0.1–0.4) with Aurivillius-Smolensky phase structures (space group A21am).
• Observed significant improvement in electrophysical properties for SrBi2Nb2-2xWxSnxO9 (x = 0.1), specifically a decrease in dielectric losses and an increase in relative permittivity.
• Demonstrated for the first time that tin (Sn) can effectively enhance the electrophysical properties of SrBi2Nb2O9, refuting prior assumptions.

Conclusions:

• Co-doping of SrBi2Nb2O9 with tin and tungsten yields novel piezoceramics with enhanced electrophysical characteristics.
• The compound SrBi2Nb2-2xWxSnxO9 (x = 0.1) exhibits promising properties for dielectric applications due to reduced losses and increased permittivity.
• Tin is confirmed as a viable and beneficial dopant for improving the performance of SrBi2Nb2O9-based materials.