This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Scientists have developed a new way to make ceramic materials that can better withstand extreme heat and continue performing reliably in sensors and actuators. The approach creates tiny structures throughout the material that give it new electrical and mechanical properties.
The international team has created what they describe as "bulk ferroelectric heterostructures" within a lead-free bismuth ferrite-barium titanate ceramic. Instead of building materials from many ultrathin layers to create useful electrical effects, the researchers used heat to reorganize the material from within. This created tiny regions with slightly different chemical compositions throughout the ceramic, each thousands of times smaller than the width of a human hair.
Together, these regions formed an internal network that changed how electricity and mechanical forces moved through the material. The study, published in Science Advances, addresses a longstanding challenge in materials science. Many of the unusual electrical and electromechanical behaviors that emerge at interfaces can be achieved in thin-film devices, but translating these effects into solid materials suitable for practical applications has proved difficult.
The new study demonstrates a way to reproduce these interface-driven effects inside a scalable ceramic architecture. Potential application areas identified by the researchers include high-temperature piezoelectric sensors, ultrasonic transducers and electromechanical actuators, particularly in situations where conventional materials face limitations due to temperature, electrical loading or long-term stability requirements. "Many of the most interesting behaviors in ferroelectric materials have historically been confined to thin films, where interfaces can be carefully engineered.
What we have shown is that similar interfacial effects can be generated throughout a solid ceramic. This creates new opportunities to control the electrical and mechanical behavior of these materials," says Dr David Hall, Reader in Ceramics, Department of Materials and the Henry Royce Institute at The University of Manchester. Using atomic-resolution microscopy, spectroscopy and computational modeling, the researchers found that the heat treatment drives nanoscale elemental partitioning, creating Bi-rich and Ba-rich regions within a coherent crystal lattice.
These compositionally distinct regions generate local electric fields, elastic strain fields and charged domain walls that influence how the material behaves under electrical and mechanical loading. One of the most striking findings was the impact on thermal performance. The researchers report a Curie temperature of 824°C (1515°F) in the engineered material, more than 350°C higher than the starting material.
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