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

具有两个稳定磁化方向的椭圆单畴纳米磁体作为逻辑开关比传统晶体管节能得多。然而，为了构建超低功耗的纳米磁逻辑和存储范例，转换它们的方法也必须是节能的。理论上已经证明，使用多铁性（磁致伸缩-压电）纳米磁体，其磁化可以随着施加在压电层上的微小静电势产生的应变而翻转，从而产生非常节能的开关方案。与其他纳米磁体开关方案相比，在时钟速率为~ 1ghz时，将开关/时钟电路的耗散降低了4个数量级。虽然这很有吸引力，但纳米磁逻辑链的一个不吸引人的特点是，为了构建流水线架构并因此保持可接受的比特传输速率，每个磁铁必须单独计时。这就需要用接触线接触每个磁极，这就增加了巨大的光刻负担。为了彻底克服这一问题，pi公司提出设计和制造一种新颖的声学时钟方案，该方案允许流水线操作，同时不需要与每个磁铁接触，从而完全减轻光刻的负担。表面声波（SAW）在衬底中发射，并随着周期性放置的质量而减慢，只要磁铁之间的间距是SAW的四分之一，就会在一组磁铁中以正确的顺序产生应变，以进行钻头传递。年代的波长。采用这种方案，栅极在室温下的能量耗散可以非常低。该项目将：(i)设计基于声学时钟磁致伸缩纳米磁铁作为逻辑开关的组合和顺序逻辑，并使用随机Landau-Lifshitz-Gilbert （LLG）方程进行广泛的模拟，以了解和优化存在热噪声的可靠性和容错性；（ii）实验证明了管道单向逻辑流，（iii）建立了表面声波（SAW）应力下纳米磁体开关动力学的综合耦合模型。这项研究将产生一种新的计算模式，其惊人的能源效率与非常小的光刻负担相结合，可以生产廉价，高产量和极低功耗的处理器。这种处理器消耗的能量非常少，可以利用从环境中获取的能量来运行。这可能会开启迄今为止难以想象的应用，比如仅由病人身体运动供电的医疗植入处理器，或者由风或交通引起的振动供电的监控桥梁和建筑物结构健康的处理器。这项研究与教育和指导的整合将导致传统的培训活动，如指导两名博士生，他们将获得先进纳米制造、纳米表征和建模的多学科技能，以及由PI和co-PI指导的SAW器件和磁致伸缩纳米磁铁的纳米制造的本科项目。S博士研究生。其他创新外展计划将包括通过数学科学创新中心（MSIC）为高中生举办纳米磁铁和计算机研讨会，并在vcu里士满地区工程少数民族项目（RAPME）项目的帮助下，通过在夏季接待代表性不足的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，并研究他们用MFM创建的磁性结构。

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.