SHF: Small: Pipelined and wireless ultra-low power straintronics: An acoustically clocked combinational and sequential nanomagnetic architecture

SHF：小型：管道式和无线超低功耗应变电子学：声学时钟组合和顺序纳米磁性架构

• 批准号: 1216614
• 负责人: Jayasimha Atulasimha
• 金额: $ 44万
• 依托单位: Virginia Commonwealth University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-01 至 2016-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1216614&HistoricalAwards=false
• 关键词: SHF; Small; Pipelined; wireless; ultra

Elliptical single-domain nanomagnets with two stable magnetization orientations are far more energy-efficient as logic switches than traditional transistors. However, the method employed to switch them must be energy-efficient as well in order to build ultra-low-power nanomagnetic logic and memory paradigms. It has been theoretically shown that using multiferroic (magnetostrictive-piezoelectric) nanomagnets, whose magnetization can be flipped with strain generated by a tiny electrostatic potential applied across the piezoelectric layer, results in a remarkably energy-efficient switching scheme. It reduces the dissipation in the switching/clocking circuit by four orders of magnitude at a clock rate of ~ 1 GHz compared to other nanomagnet switching schemes. While this is attractive, an unattractive trait of nanomagnetic logic chains is that in order to build a pipelined architecture and hence retain an acceptable bit transfer rate, each magnet must be clocked individually. This necessitates contacting each magnetic with a contact line, which imposes a Herculean lithographic burden. The PIs propose to overcome this problem completely by designing and fabricating a novel acoustic scheme for clocking that allows pipelining and at the same time does not require contacts to every magnet, thereby completely lifting the lithography burden. A surface acoustic wave (SAW) launched in the substrate, and slowed down with periodically placed masses, generates strain in an array of magnets in the correct sequence for bit transfer, as long as the spacing between the magnets is one quarter of the SAW?s wavelength. With this scheme, the energy dissipation in a gate operation at room temperature can be very low. This project will: (i) design combinational and sequential logic based on acoustically clocked magnetostrictive nanomagnets acting as logic switches, as well as perform extensive simulations using the stochastic Landau-Lifshitz-Gilbert (LLG) equation to understand and optimize reliability and fault tolerance in the presence of thermal noise; (ii) experimentally demonstrate pipelined unidirectional logic flow, and (iii) develop comprehensive coupled models for the switching dynamics of nanomagnets stressed by surface acoustic wave (SAW). This research will result in a novel computational paradigm whose astonishing energy efficiency combined with very little lithographic burden could enable the production of cheap, high yield and extremely low power processors. Such processors would consume so little energy that they can be run off the energy harvested from the environment. This could open up hitherto unimaginable applications such as medically implanted processors powered only by the motion of the patient's body, or processors that monitor the structural health of bridges and buildings while being powered by vibrations caused by wind or traffic. Integration of this research with education and mentoring will result in traditional training activities such as guiding two doctoral students who will gain multidisciplinary skills in advanced nanofabrication, nanocharacterization and modeling, as well as undergraduate projects on SAW devices and nanofabrication of magnetostrictive nanomagnets that will be mentored by the PI and co-PI?s doctoral students. Other innovative outreach programs will include holding workshops on nanomagnets and computing for high school students through the Math Science Innovation Center (MSIC) and incorporating diversity into outreach programs by hosting under-represented K-12 students in summer with the help of VCUs Richmond Area Program for Minorities in Engineering (RAPME) program. These students will perform nanolithography under supervision and study the magnetic structures they create with MFM.

具有两个稳定磁化方向的椭圆形单域纳米磁体比传统晶体管更节能地作为逻辑开关。但是，为了构建超低功率纳米磁性逻辑和内存范式，用于切换它们的方法也必须具有节能。从理论上讲，使用多丝质（磁刻曲 - 螺旋电离）纳米磁体，其磁化强度可以用由在压电层上施加的微小静电电势产生的应变来翻转，从而导致了一种伟大的能量效率开关方案。与其他纳米磁性开关方案相比，它将开关/时钟电路中的耗散降低了四个数量级。尽管这很有吸引力，但纳米磁逻辑链的一个没有吸引力的特征是，为了构建管道架构，因此保留了可接受的位传输速率，必须单独计时每个磁铁。这需要与接触线接触每个磁性，这施加了巨大的光刻负担。 PI提议通过设计和制造新型的声学方案来完全克服这个问题，该方案可以进行管道，同时不需要与每个磁铁接触，从而完全增加了光刻负担。 在底物中发射的表面声波（SAW），并用定期放置的质量放慢速度，在正确的序列中以磁体的阵列产生应变以进行位传递，只要磁体之间的间距是SAW波长的四分之一。使用此方案，在室温下，栅极操作中的能量耗散可能非常低。该项目将：（i）基于声学时钟的磁性磁性纳米磁体设计组合和顺序逻辑，用作逻辑开关，并使用随机Landau-lifshitz-gilbert（LLG）方程进行广泛的模拟，以理解和优化在存在热噪声的情况下的可靠性和容忍度； （ii）实验证明了管道的单向逻辑流，（iii）为表面声波强调的纳米磁体的开关动力学开发了全面的耦合模型（SAW）。这项研究将导致一种新颖的计算范式，其惊人的能源效率与很少的光刻负担相结合，可以使廉价，高收益和极低的电源处理器产生。这样的处理器消耗的能量很少，以至于它们可以从环境中收获的能量中跑出。这可能打开迄今无法想象的应用，例如仅由患者身体运动提供动力的医学植入处理器，或者是监控桥梁和建筑物结构健康的同时由风或交通引起的振动供电的处理器。将这项研究与教育和指导的整合将导致传统的培训活动，例如指导两个博士生，他们将获得高级纳米纳米化，纳米含量和建模的多学科技能，以及在锯子上的本科项目和纳米纳米纳米型纳米纳米人的纳米纳米纳米人的纳米纳米纳米纳米人的纳米纳米纳米人。其他创新的外展计划将包括通过数学科学创新中心（MSIC）举办有关纳米磁铁的研讨会和高中生的计算，并在夏季在VCUS Richmond Area in Engineering（Rapme）计划的VCUS Richmond Area计划的帮助下，通过在夏季举办代表性不足的K-12学生，将多样性纳入外展计划。这些学生将在监督下进行纳米光刻，并研究他们使用MFM创建的磁性结构。