Investigating the fabrication and dipole characteristics of complex ferroelectric nanoshapes

研究复杂铁电纳米形状的制造和偶极子特性

基本信息

批准号：
EP/F004869/1
负责人：
J M Gregg
金额：
$ 68.48万
依托单位：
Queen's University Belfast
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2008
资助国家：
英国
起止时间：
2008 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FF004869%2F1
关键词：
Investigating fabrication dipole characteristics complex

项目摘要

The traditional view of the ordering of polarisation or magnetisation in both ferroelectrics and ferromagnets is that local dipoles or magnetic moments are arranged into neat rows and columns, and that boundaries between neatly arranged groups must strictly conform to the crystallography of the host material (conventional stripe domains). However, recent experimental research in three-dimensionally size-constrained soft ferromagnets has revealed the existence of completely different domain states which form into vortices. As with many aspects of behaviour in ferromagnetism, analogous properties in the behaviour of the electrical polarisation in ferroelectrics is often seen, and recent modelling strongly suggests that such vortex domain states should also exist in ferroelectrics. Differences in the energetics between ferromagnets and ferroelectrics means that such unusual behaviour is only expected to dominate whenever ferroelectric dimensions are reduced to the order of ~10 nm. The creation of such small structures and the characterisation of their domain states represents a serious challenge to experimentalists involved in ferroelectric research and yet the potential for new discovery is immense. Further, simple vortex structures may only be the tip of the ice-berg, as much more exotic domain patterns have been postulated: for example some theorists have suggested the possibility of an electrostatic solenoid-analogue. Given the research performed to date, and the postulations made by theorists, the creation of three-dimensionally constrained nanostructures in ferroelectrics, and the subsequent analysis of their domain characteristics, clearly represents an exciting and challenging problem. This project will address this area of research by combining expertise in nanoscale ferroelectric fabrication with specialist characterisation techniques such as electron holography, second-harmonic near field optics, nano-Raman spectroscopy and scanning probe microscopy. The programme builds on an already established successful collaboration between ferroelectric activities in Queen's University Belfast and Cambridge, and this is augmented by international experts in specifically chosen characterisation techniques.

铁电体和铁磁体中极化或磁化顺序的传统观点是，局部偶极子或磁矩排列成整齐的行和列，并且整齐排列的组之间的边界必须严格符合基质材料的晶体学（传统的条纹）域）。然而，最近对三维尺寸受限的软铁磁体的实验研究揭示了形成涡旋的完全不同的磁畴态的存在。与铁磁性行为的许多方面一样，经常可以看到铁电体中电极化行为的类似特性，并且最近的建模强烈表明这种涡旋域状态也应该存在于铁电体中。铁磁体和铁电体之间的能量差异意味着，只有当铁电体尺寸减小到约 10 nm 的量级时，这种不寻常的行为才会占主导地位。如此小的结构的创建及其域态的表征对参与铁电研究的实验人员来说是一个严峻的挑战，但新发现的潜力是巨大的。此外，简单的涡旋结构可能只是冰山一角，因为已经假设了更多奇特的域模式：例如，一些理论家提出了静电螺线管类似物的可能性。鉴于迄今为止进行的研究以及理论家提出的假设，铁电体中三维约束纳米结构的创建以及随后对其域特征的分析，显然代表了一个令人兴奋且具有挑战性的问题。该项目将通过将纳米级铁电制造的专业知识与电子全息术、二次谐波近场光学、纳米拉曼光谱和扫描探针显微镜等专业表征技术相结合来解决这一研究领域。该计划建立在贝尔法斯特女王大学和剑桥大学铁电活动之间已经建立的成功合作的基础上，并且由国际专家在专门选择的表征技术方面得到加强。