New tools for static and dynamic imaging of antiferromagnetic textures using Bragg diffraction of coherent x rays

磁性材料在现代社会中广泛应用于各种领域，从能源生产到运输到微电子器件。反铁磁体是磁性局部存在但在宏观尺度上抵消的磁体。最近，人们认识到，反铁磁体可以用作具有增强的操作特性的新型电子器件的介质。这些材料还表现出基本科学兴趣的奇异量子特性。其中一些性质可能会在未来的量子信息技术中得到应用。任何磁体的一个基本性质是形成称为磁畴的小的均匀空间区域。这些畴对于磁电子器件的操作，特别是对于信息存储是必不可少的。为了理解反铁磁体的量子特性，并确保基于它们的设备的正确操作，对畴进行成像是必不可少的。时间分辨成像具有特别重要的意义。反铁磁畴成像是困难的。在这个项目中，一种新的成像技术，使用同步加速器产生的X射线被用来研究与量子物质的研究相关的反铁磁体中的畴的静态和动态行为，并在未来的电子学应用。该技术是唯一适合于许多域类型以前无法成像，特别是时间分辨成像。目的是了解这些材料在微观层面上的行为，以及如何控制它们。从长远来看，这些研究有望有助于更好地理解量子物质，开发更快、更小的电子设备，甚至可能有助于开发新的量子信息技术。拟议的工作将在大型国家同步加速器研究设施中进行。有一个公认的需要年轻的专家在现代同步辐射X射线散射技术。这些专家将根据这个项目进行培训，有助于实现这一长期的国家need.Technical AbstractThis项目利用一种新的方法成像反铁磁（AFM）域壁和AFM域纹理。该方法是基于共振磁布拉格散射条件下的反射相干X射线束的干涉效应。它在单次曝光中产生真实空间图像，而不需要任何图像重建程序。其独特的功能包括AFM相域的直接实空间成像，以及在毫秒到小时的时间尺度上对AFM域动态的实空间研究。该项目旨在演示和开发新成像方法的这些功能和其他几种功能。它将被应用于研究AFM域纹理和它们的动力学在几个系统的高电流的兴趣。这些系统包括具有拓扑AFM域纹理（涡旋和skyrmions）的磁体，用于AFM自旋电子学的化合物，包括拓扑AFM自旋电子学和多铁性。这种技术应提供有价值的手段，用于表征有源AFM介质中的设备状结构，在应用和基础科学研究。这应该是相关的，例如，在反铁磁体的奇异霍尔型效应的调查，如在原子力显微镜异常霍尔效应，拓扑霍尔效应等，原子力显微镜自旋电子器件工程，了解域动力学是确保设备的稳定性和高操作速度的关键。因此，将进行原型AFM设备介质的动态研究。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

Non-Technical AbstractMagnetic materials are extensively utilized in modern society in a wide variety of fields, ranging from energy generation to transportation to microelectronic devices. Antiferromagnets are the magnets in which the magnetism exists locally but cancels out on a macroscopic scale. Recently, it was realized that antiferromagnets can be used as media for novel electronic devices with enhanced operational characteristics. These materials also exhibit exotic quantum properties of fundamental scientific interest. Some of these properties may find applications in future quantum information technologies. A fundamental property of any magnet is the formation of small uniform spatial regions called domains. These domains are essential for the operation of magneto-electronic devices, especially for information storage. To understand the quantum properties of antiferromagnets, and to ensure the correct operation of devices based on them, it is essential to image the domains. Time-resolved imaging is of a special importance. Imaging antiferromagnetic domains is difficult. In this project, a novel imaging technique using the x-rays produced by synchrotrons is utilized to investigate the static and dynamic behavior of the domains in antiferromagnets relevant to the studies of quantum matter, and to prospective electronics applications. The technique is uniquely suitable for many domain types previously inaccessible to imaging, especially to time-resolved imaging. The aim is to understand how these materials behave on the microscopic level, and how to control them. In the long term, such studies are expected to contribute towards the better understanding of quantum matter, to the development of faster and smaller electronic devices, and perhaps even to novel quantum information technologies. The proposed work will be carried out at large-scale National synchrotron research facilities. There is a recognized need for young specialists in modern synchrotron x-ray scattering techniques. Such specialists will be trained under this project, contributing to the fulfillment of this long-standing national need.Technical AbstractThis Project utilizes a new method of imaging antiferromagnetic (AFM) domain walls and AFM domain textures. The method is based on interference effects in the reflected coherent x-ray beam under the condition of resonant magnetic Bragg scattering. It produces real-space images in a single exposure, without any need for image reconstruction procedures. Its unique capabilities include direct real-space imaging of AFM phase domains, and real-space studies of the AFM domain dynamics on millisecond to hours timescales. The project aims at the demonstration and development of these and several other capabilities of the new imaging method. It will be applied to study AFM domain textures and their dynamics in several systems of high current interest. These systems include magnets with topological AFM domain textures (vortices and skyrmions), compounds utilized in AFM spintronics, including topological AFM spintronics, and multiferroics. This technique should provide valuable means for the characterization of active AFM media in device-like structures utilized both in applied and fundamental science studies. This should be relevant, for example, for the investigations of the exotic Hall-type effects in antiferromagnets, such as at the AFM anomalous Hall effect, the topological Hall effect, etc. For AFM spintronics device engineering, understanding the domain dynamics is key for ensuring device stability and high operation speed. Dynamic studies of the prototype AFM device media will therefore be carried out. Exploratory in-situ studies of the AFM domain control methods relevant to spintronics applications will also be performed.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.