室温铁电在应变的SrTiO3中.
1Department of Materials Science and Engineering, Penn State University, University Park, Pennsylvania 16802-5005, USA.
Nature
|August 13, 2004
概括
应变工程使得酸薄膜中的室温铁电成为可能. 这种方法为先进的微波设备提供了卓越的均性和增强的介电性质.
科学领域:
- 材料科学 材料科学 材料科学
- 凝聚物质物理学 凝聚物质物理学
- 固态化学 固态化学
背景情况:
- 铁电材料具有接近室温的相变,对于电子设备至关重要.
- 在Ba(x) Sr(1-x) TiO(3) 等材料中进行化学替代是调整铁电过渡温度 (T(c)) 和介电常数 (epsilon(r)) 的常见方法.
- 然而,化学替代往往会导致异质性,扩大相位过渡,并对设备性能产生负面影响.
研究的目的:
- 作为一种替代方法来调整铁电膜中的铁电过渡温度 (T ((c)) 的方法,研究应变.
- 通过诱导表轴应变,在酸 (SrTiO3) 中实现室温铁电性.
- 评估压力工程铁电薄膜的统一性和介电性质,用于设备应用.
主要方法:
- 使用一种新开发的基板,对酸膜施加上向性应变.
- 采用空间分辨率成像技术来分析当地的极化状态.
- 在不同的电场下测量介电常数 (epsilon ((r)) 在GHz频率下.
主要成果:
- 长轴应变显著增加了铁电过渡温度 (T) (c) 数百度),在通常非铁电酸中诱导室温铁电.
- 在T ((c) 中,由菌株引起的增强是迄今为止报告的最大增强.
- 空间分辨率的极化成像显示了压力工程膜的异常均性,超过了化学替代产生的膜.
- 在室温下观察到高介电常数 (epsilon (r) ~7,000在10 GHz) 和强烈的电场依赖.
结论:
- 环轴应变是设计铁电性质并实现室温铁电的强大工具.
- 与化学替代相比,应变工程在薄膜均性上提供了更好的控制,从而改善了设备特性.
- 证明的高介电性质和可调性使得这些压力工程酸薄膜在微波设备应用中非常有前途.
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