Accelerated Discovery of Large Electrostrains in BaTiO₃ -Based Piezoelectrics Using Active Learning

Area of Science:

• Materials Science
• Condensed Matter Physics
• Computational Materials Science

Background:

• Discovering materials with specific properties requires navigating complex chemical and structural spaces.
• Barium titanate (BaTiO3) based materials are crucial for piezoelectric applications.
• Developing lead-free alternatives is an important environmental and technological goal.

Purpose of the Study:

• To accelerate the discovery of novel lead-free BaTiO3-based piezoelectrics with enhanced electrostrain properties.
• To identify the most effective computational strategy for guiding experimental material synthesis.
• To understand the underlying mechanisms responsible for large electrostrain in these materials.

Main Methods:

• Utilized machine learning algorithms integrated with optimization techniques.
• Employed a hybrid approach balancing exploration (uncertainty sampling) and exploitation (model prediction).
• Conducted experimental synthesis and characterization of candidate materials.
• Applied Landau theory and density functional theory (DFT) for theoretical analysis.

Main Results:

• The optimal exploration-exploitation strategy successfully guided the discovery process.
• Synthesized a new lead-free piezoelectric material: (Ba0.84Ca0.16)(Ti0.90Zr0.07Sn0.03)O3.
• Achieved the largest recorded electrostrain of 0.23% within the BaTiO3 family for this material.
• Identified tin (Sn) incorporation as a key factor enabling enhanced domain switching.

Conclusions:

• Machine learning coupled with strategic optimization significantly accelerates the discovery of advanced piezoelectric materials.
• The developed exploration-exploitation criterion is highly effective for navigating material design spaces.
• The synthesized material demonstrates promising performance for next-generation piezoelectric devices.
• Tin's role in facilitating domain wall motion is critical for achieving large electrostrain in BaTiO3-based systems.