Femtosecond switching and reading of magnetic vortex memory devices

磁涡旋存储器件的飞秒切换和读取

• 批准号: 494228-2016
• 负责人: Légaré, François
• 金额: $ 12.39万
• 依托单位: Institut national de la recherche scientifique
• 依托单位国家: 加拿大
• 项目类别: Strategic Projects - Group
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=657113
• 关键词: Femtosecond; switching; reading; magnetic; vortex

Our modern networked society keeps asking for smaller and faster memory devices, which are currently limited to GHz reading and writing speed (STT-MRAM). One way to reach the next stage, the THz regime, is using photonics. We present a magneto-optical concept that can provide both, proof of principle that the required magnetic switching works at THz frequencies, as well as understanding the processes with the required femtosecond temporal and nanoscale spatial resolution. The nanofabricated magnetic structure we will investigate for femtosecond magnetization switching is the magnetic vortex core of thin ferromagnetic discs. While magnetization circulates around this core, at its center the magnetization points either "up" or "down". Their size ~10 nm and perfect stability make them promising candidates for magnetic data storage devices operated at THz frequencies. ** Experimentally, we will follow simulations which have predicted that the magnetic field of a half-cycle MV/cm THz pulse could be used for femtosecond spin switching of these vortex cores. To combine this switching step with the required spatially localized reading step at the center of the vortex core, the THz pulse will be synchronized with a femtosecond X-ray pulse, focussed down to the nanoscale. This will enable to image the spin dynamics and thus the switching of magnetization at THz frequencies. To observe this magnetic switching at THz frequencies, we will use circularly polarized fs X-rays, applying a technique called X-ray magnetic circular dichroism (XMCD). By comparing the transmission between left and right circularly polarized pulses at specific absorption edges, one can retrieve the magnetization component normal to the plane of the vortex core. This project will enable the development of a disruptive magneto-optical technology that enables femtosecond switching and reading of magnetic vortex memory devices in collaboration with MPB Communications Inc. and few-cycle Inc., supported by international collaborators from Technion and Keio University, to scale the performance of the next generation of data storage devices.******

我们的现代网络社会不断要求更小、更快的存储设备，目前这些设备的读写速度限制在GHz(STT-MRAM)。进入下一阶段的一种方法是使用光子学，即太赫兹系统。我们提出了一个磁光概念，它既可以提供所需的磁开关工作在太赫兹频率的原理证明，也可以用所需的飞秒时间和纳米级空间分辨率来理解过程。我们将研究的用于飞秒磁化转换的纳米块状磁性结构是薄铁磁盘的磁涡核。当磁化围绕这个核心循环时，其中心的磁化点不是“向上”就是“向下”。它们的尺寸约为10 nm，稳定性极佳，有望成为工作在太赫兹频率下的磁性数据存储设备的候选材料。**在实验上，我们将遵循预测半周期mV/cm太赫兹脉冲的磁场可以用于这些涡旋核心的飞秒自旋开关的模拟。为了将这一切换步骤与涡核中心所需的空间局部化读取步骤相结合，太赫兹脉冲将与聚焦到纳米级的飞秒X射线脉冲同步。这将使得能够成像自旋动力学，从而能够在太赫兹频率上切换磁化。为了在太赫兹频率下观察这种磁开关，我们将使用圆极化的飞秒X射线，应用一种名为X射线磁性圆二色(XMCD)的技术。通过比较左、右圆偏振脉冲在特定吸收边的透过率，可以得到垂直于涡核平面的磁化分量。该项目将与MPB Communications Inc.和Low-Cycle Inc.合作，在Technion和庆应义乌大学的国际合作者的支持下，开发一种颠覆性磁光技术，实现磁涡流存储设备的飞秒切换和读取，以扩展下一代数据存储设备的性能。*