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

职业：将磁性限制在过渡金属氧化物原子层的二维范围内

• 批准号: 1751455
• 负责人: Divine Kumah
• 金额: $ 58.95万
• 依托单位: North Carolina State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-07-01 至 2023-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1751455&HistoricalAwards=false
• 关键词: CAREER; Confining; Magnetism; Two; Dimensions

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.

非技术描述：由于现代器件中材料的尺寸接近接近几个原子层的厚度，原子排列中的小偏差可能会发生，导致电子和磁性性质与大块材料的性质大不相同。使用先进的合成工具，允许组合具有不同成分的材料的原子层，可以有效地操纵原子偏差以产生新颖的效果。在这个项目中，高强度X射线被用来成像薄晶体氧化物膜层界面的原子尺度结构。从这些材料成像中获得的信息需要帮助科学家和工程师理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，以设计氧化物材料的特定组合，从而在单层氧化物材料中实现磁性。该项目对信息处理、量子计算和低功耗传感器的新型材料和设备的设计具有令人兴奋的影响。该项目提供了一个高度协作的环境，并获得先进的技术资源，用于培训本科生和研究生开发下一代先进的纳米材料。该项目提供了低成本的工具，用于可视化与晶体学相关的抽象概念，以促进公众对新技术相关晶体材料发展的理解。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加速器X射线设备，对原子进行三维非破坏性原子尺度映射，磁性钙钛矿氧化物表面和界面的电子和磁性结构。这项研究提供了对原子级薄磁性氧化物薄膜与其他极性和非极性钙钛矿材料之间界面处发生的基本相互作用的全面理解，并建立了观察到的相互作用与这些系统的物理特性之间的联系。第一性原理理论，高分辨率电子显微镜和温度相关的磁性，运输和特定元素的同步加速器X射线磁二向色性测量的组合被用来设计新的氧化物异质界面，实现在二维氧化物层的铁磁性的限制。这些材料在新型自旋电子器件中具有应用。在这项活动中使用的广泛的尖端研究工具被用来加强本科生和研究生的教育，为他们在科学研究和材料和设备工程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K-12学校的公共宣传。该奖项反映了NSF的法定使命，并被认为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来支持。

项目成果

Effect of strain on magnetic and orbital ordering of LaSrCrO3/LaSrMnO3 heterostructures

• DOI: 10.1103/physrevb.101.064420
• 发表时间: 2020-02-19
• 期刊: PHYSICAL REVIEW B
• 影响因子: 3.7
• 作者: Koohfar, Sanaz;Georgescu, Alexandru B.;Kumah, Divine P.
• 通讯作者: Kumah, Divine P.

Tuning of spin-orbit coupling in metal-free conjugated polymers by structural conformation

• DOI: 10.1103/physrevmaterials.4.085603
• 发表时间: 2020-08-28
• 期刊: PHYSICAL REVIEW MATERIALS
• 影响因子: 3.4
• 作者: Vetter, Eric;VonWald, Ian;Sun, Dali
• 通讯作者: Sun, Dali

Growth-temperature dependence of conductivity at the LaCrO 3 /SrTiO 3 (001) interface

LaCrO 3 /SrTiO 3 (001) 界面电导率与生长温度的关系

• DOI: 10.1116/1.5085334
• 发表时间: 2019
• 期刊: Journal of Vacuum Science & Technology A
• 影响因子: 2.9
• 作者: Al-Tawhid, Athby;Frick, Jordan R.;Dougherty, Daniel B.;Kumah, Divine P.
• 通讯作者: Kumah, Divine P.

Confinement of magnetism in atomically thin La0.7Sr0.3CrO3/La0.7Sr0.3MnO3 heterostructures

• DOI: 10.1038/s41535-019-0164-1
• 发表时间: 2019-05-29
• 期刊: NPJ QUANTUM MATERIALS
• 影响因子: 5.7
• 作者: Koohfar, Sanaz;Georgescu, Alexandru B.;Kumah, Divine P.
• 通讯作者: Kumah, Divine P.

Exchange bias in La 0.7 Sr 0.3 CrO 3 /La 0.7 Sr 0.3 MnO 3 /La 0.7 Sr 0.3 CrO 3 heterostructures

La 0.7 Sr 0.3 CrO 3 /La 0.7 Sr 0.3 MnO 3 /La 0.7 Sr 0.3 CrO 3 异质结构中的交换偏向

• DOI: 10.1063/1.5130453
• 发表时间: 2020
• 期刊: AIP Advances
• 影响因子: 1.6
• 作者: Olmos, Rubyann;Iturriaga, Hector;Blazer, Dawn S.;Koohfar, Sanaz;Gandha, Kinjal;Nlebedim, Ikenna C.;Kumah, Divine P.;Singamaneni, Srinivasa R.
• 通讯作者: Singamaneni, Srinivasa R.