Static and dynamic spin properties in antiferromagnetic thin films and heterostructures

反铁磁薄膜和异质结构的静态和动态自旋特性

• 批准号: 2203134
• 负责人: Jing Shi
• 金额: $ 50.28万
• 依托单位: University of California-Riverside
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-06-01 至 2025-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2203134&HistoricalAwards=false
• 关键词: Static; dynamic; spin; properties; antiferromagnetic

Non-Technical DescriptionSpintronics is an active field of research which looks at utilizing the spin of electrons for use in information processing and storage technology. Antiferromagnetic materials are important for speeding up development of spintronics because they have unique advantages over ferromagnetic materials due to their much faster spin precession dynamics and absence of spontaneous magnetic moment. However, research on antiferromagnetic thin films has been scarce. In this project, the research team comprising world leading experts elucidates important and challenging fundamental issues in thin film antiferromagnetic materials using high-quality materials synthesis, detection of antiferromagnetic spin currents using terahertz sources, antiferromagnetic domain imaging, and terahertz time-domain spectroscopy. The experimental work is complemented with theory calculations. Graduate and undergraduate students including those from including underrepresented minorities are trained with the knowledge and skills needed for future employment in the information technology industry. Technical DescriptionDue to the orders of magnitude faster spin dynamics and absence of spontaneous magnetic moment, thin film antiferromagnets present tremendous challenges in obtaining basic static and dynamic spin properties such as the antiferromagnetic ordering temperature, magnetic anisotropy, magnon dispersion, and damping parameter. In this research, a number of challenging issues are tackled using a suite of powerful capabilities developed in-house or available through collaborations with the world leading experts. These include epitaxial thin film and heterostructure growth by pulsed laser deposition and molecular beam epitaxy, detection of antiferromagnetic spin currents via spin Seebeck effect and terahertz spin pumping using both solid state terahertz source and free-electron laser, antiferromagnetic domain imaging with scanning diamond Nitrogen Vacancy-center microscope, and terahertz time-domain spectroscopy. The antiferromagnetic material properties are analyzed in conjunction with density functional theory. Specifically, the project follows the following plan: (1) grow high-quality epitaxial antiferromagnetic thin films and heterostructures for accurately determining and efficiently manipulating the antiferromagnetic order parameter; (2) generate, transport, and electrically detect spin currents in antiferromagnetic thin films both thermally and resonantly to obtain anisotropy, exchange strength, and damping parameters; and (3) control antiferromagnetic static and dynamic properties via growth and external stimuli.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.

非技术描述自旋电子学是一个活跃的研究领域，致力于利用电子自旋用于信息处理和存储技术。反铁磁材料对于加速自旋电子学的发展非常重要，因为它们具有比铁磁材料更快的自旋进动动力学和不存在自发磁矩的独特优势。然而，针对反铁磁薄膜的研究却很少。在该项目中，由世界领先专家组成的研究团队利用高质量材料合成、使用太赫兹源检测反铁磁自旋电流、反铁磁域成像和太赫兹时域光谱，阐明了薄膜反铁磁材料中重要且具有挑战性的基本问题。实验工作辅以理论计算。研究生和本科生，包括来自代表性不足的少数族裔的学生，接受信息技术行业未来就业所需的知识和技能培训。技术描述由于自旋动力学速度快几个数量级并且不存在自发磁矩，薄膜反铁磁体在获得基本的静态和动态自旋特性（例如反铁磁有序温度、磁各向异性、磁振子色散和阻尼参数）方面提出了巨大的挑战。在这项研究中，使用内部开发的或通过与世界领先专家合作获得的一套强大功能来解决许多具有挑战性的问题。其中包括通过脉冲激光沉积和分子束外延进行外延薄膜和异质结构生长、通过自旋塞贝克效应和使用固态太赫兹源和自由电子激光的太赫兹自旋泵浦检测反铁磁自旋电流、使用扫描金刚石氮空位进行反铁磁域成像-中心显微镜和太赫兹时域光谱。结合密度泛函理论分析了反铁磁材料的特性。具体而言，该项目遵循以下计划：（1）生长高质量外延反铁磁薄膜和异质结构，以精确确定和有效操纵反铁磁有序参数； （2）通过热和谐振方式产生、传输和电检测反铁磁薄膜中的自旋电流，以获得各向异性、交换强度和阻尼参数； (3) 通过生长和外部刺激控制反铁磁静态和动态特性。该奖项反映了 NSF 的法定使命，并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，被认为值得支持。