Imaging oxygen beyond the diffraction limit in ferroelectric ultra-thin films

一些材料可以在自身内部自发地产生磁场或电场，并且被称为铁磁或铁电材料。这些场通常将自己组织成一个域结构，不同的区域具有不同极性的场。从技术上讲，这有很多用途，因为我们可以组织和切换域-在硬盘驱动器或铁电随机存取存储器等设备中。当这些材料以薄层的形式生产时，畴尺寸与层厚度相匹配-这是非常有用的，因为它允许更高密度的畴被包装成更薄的膜，并且允许更少的功率来切换它们。然而，我们已经发现，当铁电薄膜非常薄时-大约10个原子层或更少-它们表现出非常不同的行为，场以复杂的方式卷曲，扭曲和变化。我们希望了解这些材料如何以及为什么会以这种奇怪的方式表现出来，这既是对传统设备的限制，也是为了看看我们是否可以利用这些效应，例如可以在多个状态而不是两个状态之间切换的设备。“看到”这种微小结构的唯一方法是使用透射电子显微镜，其现在能够具有原子分辨率，并且可以用于绘制产生电场的原子的皮米位移。这项旅行补助金将在沃里克的电子显微镜工作者与德国不莱梅的世界领先的Rosenauer教授小组之间开展新的合作，Rosenauer教授开发了一种新的电子显微镜技术，可以对这些测量具有很强的优势的材料中的原子进行成像。访问将使两个小组能够交流专门知识，在彼此的机构中建立不同的技术，共同努力了解这些材料，并将工作扩展到新的领域。

Some materials can spontaneously generate a magnetic or electrical field within themselves, and are known as ferromagnetic or ferroelectric materials. The fields usually organise themselves into a domain structure, with different regions having fields that have different polarity. Technologically, this has many uses since we can organise and switch the domains - in devices such as a hard disc drive, or a ferroelectric random access memory. When these materials are produced in the form of a thin layer the domain size matches the layer thickness - which is very useful since it allows both a higher density of domains to be packed into thinner films and less power to switch them. However, we have discovered that when ferroelectric films are made extremely thin - around ten atomic layers or less - they exhibit very different behaviour with fields that curl, twist and change in complicated ways. We would like to understand how and why the materials behave in this strange way, both for the limitations on conventional devices and also to see if we can exploit these effects, e.g. for devices that could switch between multiple states rather than just two.The only way to 'see' such tiny structures is to use transmission electron microscopy, which is now capable of atomic resolution and can be used to map the picometer displacements of the atoms that produce the electric fields. This travel grant will develop a new collaboration between electron microscopists at Warwick who have been working on these materials and the world-leading group of Prof. Rosenauer in Bremen, Germany, who has developed a new electron microscopy technique to image the atoms in a material that has strong advantages for these measurements. The visits will allow the two groups to exchange expertise, establish their different techniques in each other's institutions, work together to understand these materials, and expand the work into new fields.