Mesopores induced zero thermal expansion in single-crystal ferroelectrics

Area of Science:

• Materials Science
• Solid State Physics
• Nanotechnology

Background:

• Zero thermal expansion materials are crucial for high-precision instruments.
• Existing methods like composites, solid solutions, and doping have limitations.
• Microstructure-controlled zero thermal expansion via interfaces or surfaces remains largely unexplored.

Purpose of the Study:

• To investigate zero thermal expansion behavior in ferroelectric materials.
• To explore the role of microstructure, specifically mesopores, in achieving zero thermal expansion.
• To demonstrate a novel strategy for designing zero thermal expansion materials.

Main Methods:

• Fabrication of single-crystal ferroelectric lead titanate (PbTiO3) fibers.
• Incorporation of large-scale faceted and enclosed mesopores within the fibers.
• Characterization of volumetric thermal expansion coefficient from 293 K to 623 K.

Main Results:

• Observed impressive zero thermal expansion (volumetric thermal expansion coefficient: -1.41 × 10^-6 K^-1) in PbTiO3 fibers.
• Attributed the zero thermal expansion to a synergetic effect between positive thermal expansion near mesopores and negative thermal expansion from ferroelectricity.
• Demonstrated the influence of oxygen-based polarization screening on thermal expansion.

Conclusions:

• Surface construction in negative thermal expansion ferroelectric materials is a viable strategy for achieving zero thermal expansion.
• Engineered mesopores in ferroelectric materials can lead to unique thermal expansion properties.
• This study opens new avenues for designing advanced materials for demanding applications.