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

一些材料可以自发地在自身内部产生磁场或电场，被称为铁磁性或铁电材料。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的场具有不同的极性。从技术上讲，这有很多用途，因为我们可以组织和交换域-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，磁区的大小与层的厚度匹配-这是非常有用的，因为它允许更高密度的磁区被填充到更薄的薄膜中，并且切换它们的功率更小。然而，我们已经发现，当铁电薄膜非常薄-大约十个原子层或更少-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。我们想要了解这种材料是如何以及为什么会以这种奇怪的方式表现出来的，这既是因为传统设备的局限性，也是为了看看我们是否可以利用这些效应，例如，对于可以在多个状态之间转换而不是只有两个状态的设备。“看到”如此微小结构的唯一方法是使用透射电子显微镜，它现在能够进行原子分辨率，并可以用来绘制产生电场的原子的皮米位移。这笔旅行补助金将在华威大学从事这些材料研究的电子显微镜专家和德国不来梅的罗森奥尔教授的世界领先团队之间展开新的合作。罗森奥尔教授开发了一种新的电子显微镜技术，可以对这种材料中的原子进行成像，这种材料在这些测量方面具有很强的优势。访问将使两个小组能够交流专业知识，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.