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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 9: (Multi)ferroic States: From Fundamentals to Applications (IV)
KFM 9.4: Vortrag
Dienstag, 18. März 2025, 12:30–12:45, H9
Step sintering process on sol-gel synthetized Bi0.5Na0.5TiO3 for enhanced temperature stability of relaxor ferroelectric state and energy storage properties — •Thomas Fourgassie1, Cécile Autret-Lambert1,2, and Pierre-Eymeric Janolin2 — 1Laboratoire GREMAN, UMR 7347 Université de Tours, CNRS, INSA CVL, Université de Tours UFR Sciences & Techniques, 37200 Tours, France — 2Laboratoire SPMS, UMR 8580 Université Paris-Saclay, CNRS, CentraleSupélec, 91190 Gif-sur-Yvette, France
With the ever-growing need for energy in our society, researchers are striving to obtain new materials with better energy storage properties capable of replacing current lead-based materials. Among all lead-free materials that have been synthesized, Bi0.5Na0.5TiO3 (BNT) has attracted the attention of many. The main reasons are his high temperature of maximum permittivity called Tm at 320°C, a huge maximum polarization and relaxor ferroelectric properties making his phase transition very diffuse in temperature. However, the good energy storage properties only apply at a temperature higher than the depolarization temperature Td (200°C). Usually, to reduce Td, researchers either make solid solutions with other perovskite ceramics or use donor dopants. Here we show the results we obtained while keeping the pristine BNT phase by optimizing the sol-gel synthesis process used. The BNT exhibits sub-micrometric grain size thanks to a multi-step sintering process lowering Td (around 160°C). This BNT has enhanced relaxor ferroelectric at lower temperatures. Results about donor dopants reducing dielectric losses on this BNT will also be shown.
Keywords: energy storage; dielectric; ferroelectric; relaxor; synthesis