在 (Sr,Ca)3Sn2O7及以上的混合不当铁电:在n=2个Ruddlesden-Popper阶段的铁电过渡温度和耐受性因子之间的通用关系
Suguru Yoshida1, Hirofumi Akamatsu, Ryosuke Tsuji1
1Department of Material Chemistry, Graduate School of Engineering , Kyoto University , Katsura Nishikyo-ku , Kyoto 615-8510 , Japan.
Journal of the American Chemical Society
|October 24, 2018
概括
混合不当的铁电使用几何扭曲来产生两极化. 研究人员发现库里温度 (TC) 和新型铁电材料的戈德施密特容忍因子 (t) 之间存在线性关系.
科学领域:
- 材料科学
- 固态物理
- 晶体学
背景情况:
- 混合不适当的铁电利用几何扭曲来实现极化,为新型铁电和多铁材料提供了途径.
- 目前使用组理论和第一原理的设计方法准确地预测了晶体对称性,但与库里温度 (TC) 等关键参数进行斗争.
研究的目的:
- 在混合不当铁电中建立TC和Goldschmidt容忍因子 (t) 之间的预测性,定量关系.
- 研究Ruddlesden-Popper (RP) 系统中铁电过渡的纯几何 (离子大小) 影响.
主要方法:
- 使用n = 2 Ruddlesden-Popper (RP) A3B2O7系统,特别是 (Sr1-xCax) 3Sn2O7,以研究几何效应.
- 专注于缺乏电子铁电扭曲机制的材料 (例如d0和6s2离子).
- 实验确定了各种成分的TC,并将其与耐受性因子 (t) 相对应.
主要成果:
- 观察到一个铁电到电的过渡,TC=410 K对于Sr3Sn2O7.
- 发现TC随着Ca2+含量增加 (降低t) 线性增加至800K.
- 证明这种线性TC-t关系适用于所有已知的A3B2O7混合不当铁电.
结论:
- 根据离子大小不匹配,建立了TC和晶体化学描述因子Goldschmidt容忍因子 (t) 之间的预测相关性.
- 这一发现为估计混合不当铁电器中的TC提供了指导方针.
- 补充了现有的组理论和第一原则设计方法来发现新的铁电材料.
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