Department of Materials Science, The University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States.
ACS Nano. 2011 Jan 25;5(1):640-6. doi: 10.1021/nn102884s. Epub 2010 Dec 16.
Oxide heterostructure superlattices constitute a new family of materials with tunable ferroelectric properties. While theoretical models predict the presence of nanosized ferroelectric domains in these films, they had not been observed as the magnitude of the response functions challenges the limits of experimental detection. Here, a new protocol in a precise variant of piezoforce microscopy is used to image domains in BaTiO(3)/SrTiO(3) superlattices. Comparison of experimentally determined polarization to predictions of phase-field calculations is in quantitative agreement. Additionally, a combination of theory and experiment is used to determine the magnitude of internal electric field within the thin film, in a procedure that can be generalized to all ferroelectric films.
氧化物异质结构超晶格构成了一类具有可调铁电性能的新材料。虽然理论模型预测这些薄膜中存在纳米级铁电畴，但由于响应函数的大小挑战了实验检测的极限，因此这些畴一直未被观察到。在这里，一种新的协议在压电力显微镜的精确变体中被用来成像 BaTiO(3)/SrTiO(3)超晶格中的畴。实验确定的极化与相场计算的预测之间的比较是定量一致的。此外，通过理论和实验的结合，在可以推广到所有铁电薄膜的程序中，确定了薄膜内部电场的大小。
