CAREER: Thermal stability and scaling of nanoscale spin-electronic devices based on novel inverse-Heusler alloys

从智能手机到笔记本电脑，许多高科技设备都使用纳米级电子开关来实现其功能，这些开关完全依赖于电子的电荷特性。电子还有另一种固有性质，叫做自旋，直观上类似于一个旋转的带电球。在自旋电子学或自旋电子学领域，利用电子的自旋特性来制造新的器件。例如，磁性硬盘驱动器中的读头传感器是一种自旋电子器件。自旋电子学的下一个技术步骤是实现自旋开关，与基于电荷的技术相比，非挥发性的额外好处将是新颖的。但是，为了实现具有长寿命和高能效的纳米级自旋开关，一些与性能相关的参数需要进行重大改进。一种方法是修改自旋电子器件内部的材料组件来解决这些挑战。这就是研究计划的目的。几种预先确定的新型磁性材料及其组合将使用薄膜生长和纳米级器件制造技术在先进的自旋电子器件中实现。纳米级自旋器件的开关、缩放、能效和速度特性将被表征，以测试材料的可行性。该研究计划的成功实施有可能带来高回报，并导致节能的自旋装置。本课程将为研究生、本科生和高中生提供材料、器件物理和器件设计、制造和表征方面的广泛培训和教育。该项目将积极致力于通过伊利诺斯州南部地区的几项协同推广工作，促进本科生和当地高中生对科学、技术和工程学科的兴趣。自旋电子学被认为是解决当前半导体器件缩放问题的一种有前途的技术。在紧急自旋转移扭矩随机存取存储器中，除了ON/OFF比之外，热稳定性和开关电流密度等参数对于此类技术在20nm节点以下的可行性非常重要。在本提案中，将研究自旋器件配置中的几种新材料组合，以直接解决自旋电子学技术的挑战性问题。研究了几种具有垂直磁各向异性和高自旋极化的反荷斯勒磁材料。磁隧道结和自旋转移扭矩器件将设计，制造和测试其开/关比，开关电流/效率和热稳定性。在初始阶段，将在微米级器件上测试隧道磁阻特性，以确定各种材料组合的可行性。在该项目的第二阶段，将对器件进行低于20纳米的测试，以研究所有相关参数的缩放行为。纳米尺度的自旋操纵在器件几何将进行利用形状各向异性。基本磁性能的协同界面表征将在不同的国家实验室设施中使用同步辐射完成。项目目标的成功实现可以将自旋电子学技术更好地集成到当前的半导体器件中。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Many high-tech gadgets from smartphones to laptops employ nanoscale electronic switches for their functionality that rely exclusively on the charge property of the electron. The electron also has another intrinsic property, called spin, which is intuitively analogous to a spinning ball of charge. In the area of spin-electronics, or spintronics, the spin property of electron is exploited to make new devices. For example, the read-head sensor in magnetic hard-disk drives is a spintronic device. The next technology step for spintronics is to realize a spin-switch where the added benefit of non-volatility will be novel compared to charge-based technologies. But several performance-related parameters require significant improvement in order to achieve a nanoscale spin-switch with long lifetime and high energy-efficiency. One approach is to modify the material components inside spintronic devices to address the challenges. Such is the objective of the research plan. Several pre-identified novel magnetic materials and their combinations will be implemented in an advanced spintronic device using thin-film growth and nanoscale device fabrication techniques. The nanoscale spin devices will be characterized for their switching, scaling, energy-efficiency, and speed characteristics to test the feasibility of the materials. Successful implementation of the research plan has the potential for a high payoff and lead to energy-efficient spin-devices. A broad-based training and education of several graduate, undergraduate, and high school students will be accomplished in materials, device physics and device design, fabrication and characterization. The program will actively focus on promoting interest in science, technology and engineering disciplines among undergraduates and local high school students through several synergistic outreach efforts within the local southern Illinois area.Spintronics is recognized as a promising technology to address the scaling problems of current semiconductor devices. In emergent Spin-Transfer Torque Random-Access Memory, parameters such as thermal stability and switching current density, in addition to ON/OFF ratio, are important for such technologies to be viable below the 20 nm node. In this proposal, several new material combinations will be investigated in spin device configurations to directly address the challenging issues of spintronics technology. Several inverse-Heuslers magnetic materials that show perpendicular magnetic anisotropy and high spin-polarization will be investigated. Magnetic Tunnel Junction and Spin-transfer Torque devices will be designed, fabricated and tested for their ON/OFF ratio, switching current/efficiency, and thermal stability. In the initial phase, the tunnel magnetoresistance properties will be tested on micron-scale devices to establish the viability of the various materials combinations. In the second phase of the project, devices will be tested down to sub-20 nm level to investigate the scaling behavior of all relevant parameters. Nanoscale manipulation of spins in a device geometry will be conducted using shape anisotropy. Synergistic interface characterization of fundamental magnetic properties will be accomplished using synchrotron radiation at various national lab facilities. Successful implementation of project goals can lead to greater integration of spintronics technologies into current semiconductor devices.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.