Magnetic skyrmions in chiral multilayers

在这个项目中，我们将研究磁skyrmions，具有非平凡拓扑结构的自旋纳米漩涡。它们在室温下出现在适当设计的磁性多层膜中，是下一代数据存储技术的候选者。十多年来，互联网的碳足迹已经超过了商业航空旅行的碳足迹，其中大部分能源用于物理旋转硬盘，向其中写入数据，以及写入和刷新易失性存储器。使用自旋力矩沿着晶体驱动skyrmions需要比在理想条件下驱动磁畴小几个数量级的电流密度，但这在这些系统中迄今为止还没有看到。磁skyrmion提供了前景，大大减少所需的能量写入和存储的数字数据，如果他们的属性可以控制。本项目的建议重点是在室温下的skyrmion的流动性的影响下，通过将skyrmion轴承多层的另一种材料的适当属性的顶部提供增强的自旋轨道扭矩。学生将生长异质结构，在结构上和磁性上将其排列，然后将其图案化为纳米级器件，其中可以通过合理的电流实现产生自旋扭矩所需的高电流密度。Skyrmion成核和运动，然后将通过磁成像研究。

In this project we will study magnetic skyrmions, nanoscale swirls of spins that possess a non-trivial topology. They appear in properly designed magnetic multilayers at room temperature and are candidates for next-generation data storage technology. It is now over a decade since the carbon footprint of the internet grew larger than that of commercial air travel, much of this energy is used to physically spin hard disks, write data to them, and write and refresh volatile memory. To drive skyrmions along a crystal using spin torque requires several orders of magnitude less current density then driving magnetic domains under ideal conditions, but this is not seen in practice in these systems so far. Magnetic skyrmions offer the prospect of vastly reducing the energy needed to write and store digital data if their properties can be controlled.The proposed focus of this project is the mobility of skyrmions at room temperature under the influence of enhanced spin-orbit torques provided by placing the skyrmion-bearing multilayer on top of another material with suitable properties. The student will grow the heterostructures, characterise them structurally and magnetically, and then pattern them into nanoscale devices in which the high current densities needed to generate spin-torques can be achieved with reasonable currents. Skyrmion nucleation and motion will then be studied by means of magnetic imaging.