Lead-Free Polycrystalline Ferroelectric Nanowires with Enhanced Curie Temperature

Ferroelectrics are important technological materials with wide-ranging applications in electronics, communication, health, and energy. While lead-based ferroelectrics have remained the predominant mainstay of industry for decades, environmentally friendly lead-free alternatives are limited due to relatively low Curie temperatures (TC) and/or high cost in many cases. Efforts have been made to enhance TC through strain engineering, often involving energy-intensive and expensive fabrication of thin epitaxial films on lattice-mismatched substrates. Here, a relatively simple and scalable sol–gel synthesis route to fabricate polycrystalline (Ba_0.85Ca_0.15)(Zr_0.1Ti_0.9)O₃ nanowires within porous templates is presented, with an observed enhancement of TC up to ~300 °C as compared to ~90 °C in the bulk. Our results offer a cost-effective solution-based approach for strain-tuning in a promising lead-free ferroelectric system, thus widening their current applicability.

Figure: Nanowires of (Ba_0.85Ca_0.15)(Zr_0.1Ti_0.9)O₃ (BCT-0.5BZT) are grown using a template-aided sol–gel synthesis route. These are found to have an enhanced ferroelectric Curie temperature (T_C) of ~300 °C as compared to ~90 °C in the bulk (inset).