Lead-Free Polycrystalline Ferroelectric Nanowires with Enhanced Curie Temperature

5 years ago

Lead-Free Polycrystalline Ferroelectric Nanowires with Enhanced Curie Temperature

Canlin Ou, Anuja Datta, Sohini Kar-Narayan, Marco Fornari, Yonatan Calahorra, Suman-Lata Sahonta, Pedro E. Sanchez-Jimenez, Rabih Al Rahal Al Orabi

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 (T C) and/or high cost in many cases. Efforts have been made to enhance T C 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 (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 nanowires within porous templates is presented, with an observed enhancement of T C up to ≈300 °C as compared to ≈90 °C in the bulk. By combining experiments and theoretical calculations, this effect is attributed to the volume reduction in the template-grown nanowires that modifies the balance between different structural instabilities. The results offer a cost-effective solution-based approach for strain-tuning in a promising lead-free ferroelectric system, thus widening their current applicability. Nanowires of (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 (BCT-0.5BZT) are grown using a template-aided sol–gel synthesis route. These are found to have enhanced ferroelectric Curie temperature (T C) of ≈300 °C as compared to ≈90 °C in the bulk. BCT-0.5BZT in the bulk has limited applicability due to its room-temperature T C. The studies thus offer a cost-effective solution, by achieving enhanced T C via strain-tuning in BCT-0.5BZT nanowires.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/adfm.201701169