A nanoscale shape memory oxide
A nanoscale shape memory oxide
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纳米级形状记忆氧化物
DOI：
10.1038/ncomms3768
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发表时间：
2013-11-01
影响因子：
16.6
通讯作者：
Ramesh, Ramamoorthy
中科院分区：
文献类型：
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作者：
Zhang, Jinxing;Ke, Xiaoxing;Ramesh, Ramamoorthy
近年来，刺激响应型形状记忆材料引起了人们极大的研究兴趣，人们致力于改善其机械驱动性能。受纳米机电装置的需求驱动，因此需要具有大机械应变的材料，特别是在纳米级水平。在这里，我们报告的发现，在纳米级的铁酸铋的一个大的形状记忆效应。最大应变可达~14%，体积功密度可达~600±90 J cm− 3，这与马氏体相变有关。通过单一步骤，已经可逆地实现了通过热激活或电场来控制相变，而无需外部恢复应力的辅助。尽管对于真实的器件，必须考虑到诸如滞后、微裂纹等方面，但这种氧化物的大的形状记忆效应超过了大多数合金，因此，证明了其本身是一种在最先进的纳米系统中具有潜在用途的非凡材料。
Stimulus-responsive shape-memory materials have attracted tremendous research interests recently, with much effort focused on improving their mechanical actuation. Driven by the needs of nanoelectromechanical devices, materials with large mechanical strain, particularly at nanoscale level, are therefore desired. Here we report on the discovery of a large shape-memory effect in bismuth ferrite at the nanoscale. A maximum strain of up to ~14% and a large volumetric work density of ~600±90 J cm−3can be achieved in association with a martensitic-like phase transformation. With a single step, control of the phase transformation by thermal activation or electric field has been reversibly achieved without the assistance of external recovery stress. Although aspects such as hysteresis, microcracking and so on have to be taken into consideration for real devices, the large shape-memory effect in this oxide surpasses most alloys and, therefore, demonstrates itself as an extraordinary material for potential use in state-of-art nanosystems.