Anisotropy Factors and Electromechanical Coupling in Lead-Free 1-3-Type Composites

Area of Science:

• Materials Science
• Solid State Physics
• Nanotechnology

Background:

• Lead-free piezoelectric materials are crucial for sustainable electronic devices.
• Developing materials with high electromechanical coupling and anisotropy is a key challenge.
• Existing lead-free options often compromise on performance compared to lead-based counterparts.

Purpose of the Study:

• To investigate the electromechanical properties and anisotropy factors of novel lead-free 1-3-type composites.
• To demonstrate the potential for large piezoelectric anisotropy and significant electromechanical coupling.
• To compare the performance of these composites with conventional lead-containing piezoelectric materials.

Main Methods:

• Composites were designed with two single-crystal components and a polymer matrix.
• One component featured domain-engineered [001]-poled alkali niobates-tantalates rods.
• The second component consisted of Li₂B₄O₇ inclusions within the polymer matrix, exhibiting a 1-0-3 connectivity.

Main Results:

• Simultaneous achievement of large piezoelectric coefficient anisotropy and electromechanical coupling factor (ECF) anisotropy was demonstrated.
• High ECFs (up to -0.9) were obtained within specific ranges of component volume fractions and inclusion aspect ratios.
• The influence of the anisotropic matrix's elastic properties on overall composite performance was analyzed.

Conclusions:

• The studied lead-free 1-3-type composites exhibit substantial piezoelectric anisotropy and electromechanical coupling.
• These materials present a viable and advantageous alternative to lead-based piezoelectric ceramics.
• Optimized composite design offers a pathway to high-performance, environmentally friendly piezoelectric applications.