CAREER: Confining Magnetism to Two-Dimensions in Transition Metal Oxide Atomic Layers

非技术描述：随着现代设备中材料的尺寸接近几个原子层的厚度，原子排列中可能会出现微小的偏差，导致电子和磁性与块状材料的性质截然不同。使用先进的合成工具，允许将不同组成的材料的原子层组合在一起，可以有效地操纵原子偏差，以产生新的效果。在这个项目中，高强度X射线被用来成像薄晶体氧化物薄膜层界面的原子尺度结构。需要通过对这些材料进行成像获得的信息来帮助科学家和工程师了解为什么一些氧化物材料在厚度减少到几个原子层时会失去有用的磁性。X射线结果与高分辨率电子显微镜、磁性和传输测量以及理论计算相结合，以设计特定的氧化物材料组合，以实现单层氧化物材料的磁性。该项目对信息处理、量子计算和低功率传感器的新型材料和设备的设计具有令人兴奋的意义。该项目为培训本科生和研究生开发下一代先进纳米材料提供了一个高度协作的环境和获得先进技术资源的途径。该项目提供了低成本的工具，用于可视化与结晶学相关的抽象概念，以促进公众对与技术相关的新晶体材料的开发的了解。技术细节：该项目使用阿贡国家实验室和伯克利国家实验室最先进的同步辐射X射线设备，对磁性钙钛矿氧化物表面和界面的原子、电子和磁性结构进行三维非破坏性原子尺度测绘。这项研究全面了解了原子薄磁性氧化物薄膜与其他极性和非极性钙钛矿材料之间的界面上发生的基本相互作用，并建立了观察到的相互作用与这些系统的物理性质之间的联系。结合第一性原理理论、高分辨电子显微镜和随温度变化的磁、输运和元素相关的同步X射线二色性测量，设计了一种新型的氧化物异质界面，以实现对二维氧化层中铁磁性的限制。这些材料在新型自旋基电子器件中有应用。本次活动使用了广泛的尖端研究工具，以加强本科生和研究生的教育，为他们在科学研究和材料与设备工程领域的职业生涯做好准备。该项目的一个重要组成部分是开发低成本的增强现实工具，用于可视化复杂的原子和电子结构，用于课堂教学和面向K-12学校的公共宣传。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

NON-TECHNICAL DESCRIPTION: As the dimensions of materials in modern devices approach thicknesses close to a few atomic layers, small deviations in atomic arrangements can occur leading to electronic and magnetic properties which differ vastly from the properties of the bulk materials. Using advanced synthesis tools which permit the combination of atomic layers of materials with different compositions, the atomic deviations can be effectively manipulated to produce novel effects. In this project, high-intensity X-rays are used to image the atomic-scale structure of the interfaces of layers of thin crystalline oxide films. The information gained from imaging these materials is required to help scientists and engineers understand why some oxide materials lose their useful magnetic properties when their thicknesses are reduced to a few atomic layers. The X-ray results are combined with high-resolution electron microscopy, magnetic and transport measurements, and theoretical calculations to design specific combinations of oxide materials to achieve magnetism in single layers of oxide materials. This project has exciting implications for the design of novel materials and devices for information processing, quantum computing and low-powered sensors. This project provides a highly collaborative environment and access to advanced technical resources for training undergraduate and graduate students in the development of the next generation of advanced nanoscale materials. The project provides low-cost tools for visualizing abstract concepts related to crystallography to foster the public understanding of the development of new technologically-relevant crystalline materials.TECHNICAL DETAILS: This project uses state-of-the-art synchrotron X-ray facilities at the Argonne National Laboratory and the Berkeley National Laboratory to carry out three-dimensional non-destructive atomic-scale mapping of the atomic, electronic and magnetic structures of magnetic perovskite oxide surfaces and interfaces. This research provides a comprehensive understanding of the fundamental interactions which occur at the interfaces between atomically-thin magnetic oxide films and other polar and non-polar perovskite materials and establishes a link between the observed interactions and the physical properties of these systems. A combination of first principles theory, high-resolution electron microscopy and temperature-dependent magnetic, transport and element-specific synchrotron X-ray magnetic dichroism measurements is used to design novel oxide heterointerfaces for achieving the confinement of ferromagnetism in two-dimensional oxide layers. These materials have applications in novel spin-based electronic devices. The wide range of cutting-edge research tools utilized in this activity are used to enhance the education of undergraduate and graduate students to prepare them for careers in scientific research and materials and device engineering. An important component of this project is the development of low-cost augmented reality tools for visualizing complex atomic and electronic structures for classroom instruction and public outreach to K-12 schools.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.