权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

EAGER-Generation of Perpendicularly Polarized Spin Current from the Spin-Orbit Effects in Ferromagnetic Thin Film Structures for Memory Applications

存储器应用中的铁磁薄膜结构中的自旋轨道效应急切地产生垂直极化的自旋电流

基本信息

批准号：
1738679
负责人：
Xin Fan
金额：
$ 7.95万
依托单位：
University of Denver
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-06-01 至 2018-11-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1738679&HistoricalAwards=false
关键词：
EAGER Generation Perpendicularly Polarized Spin

项目摘要

To accommodate the ever-increasing demand of computational power, there has been a great effort in searching for new types of memories that are fast and energy-efficient. Magnetic random access memory, which uses magnetism to store information and electricity to read/write information, is a potential candidate as the new generation of memory because magnetism is intrinsically non-volatile and switches fast. The main technical challenge is to reduce the amount of energy it takes to switch the magnetization in the writing process of the magnetic random access memory. This project aims to explore an efficient way to switch the magnetization by using a spin current, i.e. a flow of electron spins, with a specially engineered spin orientation. This work will provide transformative information on how to generate perpendicular spins from magnetic structures, which will significantly lower the power consumption in magnetic random access memories with perpendicular magnetizations. The outcome from this research will lead to a significant advance in data storage and information technologies. The spin-orbit effects have been demonstrated to be a promising way to convert an electric current into a spin current that can efficiently switch a magnetization. However, thus far the spin currents generated by the spin-orbit effects are constrained by thin film geometries and therefore are only polarized in-plane. It is inefficient to use an in-plane polarized spin current to switch a perpendicular magnetization, which is technically attractive in the application of memories due to their scalability and thermal stability. In this proposal, the investigator plan to explore the generation of a perpendicularly polarized spin current using the spin-orbit effects in ferromagnetic structures, which is based on the hypothesis that the ferromagnetism provides an additional control on the spin orientation. Two complementary structures will be investigated: the spin filtering, where the spin polarization is aligned with the magnetization, and spin rotation, where the spin polarization is rotated about the magnetization. This project leverages on unique expertise in detecting the spin torque on magnetization using the sensitive magneto-optic-Kerr-effect magnetometry and ferromagnetic resonance-based magnetometry. The specific tasks in the project are (1) quantifying the efficiency to generate perpendicularly polarized spin current in the two ferromagnetic structures and (2) designing efficient device for switching magnetization with a fast switching time. This study will also provide important insights in the comprehensive spin-orbit effects from magnetic structures.

为了适应日益增长的计算能力需求，人们一直在努力寻找快速和节能的新型存储器。磁性随机存取存储器利用磁性来存储信息，利用电力来读写信息，由于磁性本质上是非易失性的，开关速度很快，因此是新一代存储器的潜在候选者。主要的技术挑战是减少在磁随机存取存储器的写入过程中切换磁化所需的能量。这个项目旨在探索一种有效的方法，通过使用自旋电流，即具有特殊设计的自旋取向的电子自旋流动来切换磁化强度。这项工作将为如何从磁性结构中产生垂直自旋提供变革性的信息，这将显著降低垂直磁化的磁随机存取存储器的功耗。这项研究的结果将导致数据存储和信息技术的重大进步。自旋轨道效应已被证明是一种很有前途的将电流转换为自旋电流的方法，可以有效地切换磁化强度。然而，到目前为止，由自旋-轨道效应产生的自旋电流受到薄膜几何结构的限制，因此只在平面内极化。使用面内极化的自旋电流来切换垂直磁化强度是低效的，由于其可扩展性和热稳定性，在存储器的应用中在技术上具有吸引力。在这个方案中，研究人员计划利用铁磁结构中的自旋轨道效应来探索垂直极化自旋流的产生，这是基于铁磁性对自旋取向提供额外控制的假设。我们将研究两种互补的结构：自旋过滤，其中自旋极化与磁化强度对齐；以及自旋旋转，其中自旋极化围绕磁化强度旋转。该项目利用独特的专业技术，使用灵敏的磁光克尔效应磁测量和基于铁磁共振的磁测量来检测磁化时的自旋扭矩。该项目的具体任务是：(1)量化在两种铁磁结构中产生垂直极化自旋电流的效率；(2)设计高效的开关磁化装置，开关时间短。这项研究还将对磁结构的综合自旋-轨道效应提供重要的见解。