Ultra-fast energy efficient ferrimagnetic memory

该项目的目标是深入了解一类新的磁性材料：亚铁磁体的物理特性，并创建一种新的存储设备，以解决当今技术无法解决的速度和能量瓶颈。这项研究的成功将为下一代信息和通信技术树立一个重要的里程碑。该研究与工业需求密切相关，以提供新的方向，从而可能推动另一波创新，促进社会经济增长。这种影响是变革性的，因为它旨在发现新型功能纳米材料以及高密度，高速和超高效率器件的新物理。前沿研究也将产生巨大的教育影响，因为该研究培训了不同教育水平的学生，从高中到本科/研究生院（包括妇女和少数民族）以及学校教师在物理科学，工程和计算机科学的跨学科和多学科和新兴领域，通过PI参与加州大学洛杉矶分校的推广计划。这些新兴学科的培训将提供多样化的人力资本，精通科学方法并在应用方面经验丰富。教育的影响进一步扩大了现有的推广计划建立在加州大学洛杉矶分校NSF工程研究中心。 在大数据和人工智能时代，超快和节能的存储设备对于解决当今计算挑战的速度和能耗限制至关重要。 拟议的研究旨在实现一种完全不同的基于绝缘亚铁磁材料的存储设备，由于巨大的内部交换场，这种存储设备可以以太赫兹的速度运行。特别地，这些材料通常具有低阻尼，从而实现高能量效率。主要任务是理解和控制近补偿亚铁磁体的动力学，并建立亚铁磁原型存储器。 为了实现这一目标，本研究将从三个方面研究一系列新型绝缘亚铁磁体：（1）通过电学表征、泵浦探测、X射线和中子技术，了解补偿亚铁磁体与大自旋轨道耦合层之间的基本开关机制和界面交换耦合;（2）通过反常霍尔效应和磁阻效应实现补偿亚铁磁有序的电操纵;（3）利用超短脉冲和皮秒范围内的光泵浦探测实现它们的超快动力学。从根本上说，这项研究将使界面耦合和亚铁磁动力学的理解，从而产生新的开关机制。 该奖项反映了NSF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。

The goal of this project is to achieve an in-depth understanding of the physics of a new class of magnetic material: ferri-magnets, and to create a new kind of memory device to resolve the bottleneck in speed and energy beyond today's technologies. The success of the proposed research will surely set an important milestone for next-generation information and communications technology. The research is closely aligned with industrial needs to provide new directions, which may thus fuel another wave of innovation for socio-economic growth. The impact is transformative because it aims at the discovery of novel functional nanomaterials as well as the new physics for high density, high speed, and ultra-high efficient devices. The forefront research will also have a vast educational impact since the research trains students with various education levels, from high school to undergraduate/graduate school (including women and minorities) as well as school teachers in this inter- and multi-disciplinary and emerging fields of physical science, engineering, and computer science, through PI's participation of the outreach programs at UCLA. The training in these emerging disciplines will provide a diverse human capital, versed in scientific methods and experienced in the applications. The educational impact is further amplified by the existing outreach programs established in the UCLA NSF Engineering Research Center. Ultra-fast and energy-efficient memory devices are critical to resolving the limit of speed and energy dissipation for today's computing challenges in the era of big data and artificial intelligence. The proposed research is aimed at realizing a radically different class of memory devices based on insulating ferrimagnetic materials, which can operate at terahertz speed due to the enormous internal exchange field. In particular, these materials usually have low damping, enabling high energy efficiency. The major tasks are to understand and control the dynamics of nearly compensated ferri-magnets and to build ferri-magnetic prototype memories. To accomplish the objective, the proposed research will investigate a series of new insulating ferri-magnets from three perspectives: (1) understanding the fundamental switching mechanism and the interfacial exchange coupling between a compensated ferrimagnet and a large spin-orbit-coupling layer through electrical characterizations, pump-probe, x-ray, and neutron techniques; (2) enabling electrical manipulation of the compensated ferrimagnetic order to be demonstrated by anomalous Hall and magnetoresistance effects; (3) realizing their ultrafast dynamics using electronic ultrashort pulses and optical pump-probing in the picosecond regime. Fundamentally, the research will enable the understanding of the interface coupling and the ferri-magnetic dynamics, resulting in new switching mechanisms. It may provide a new framework for employing spintronics in quantum technology.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.