Skyrmion materials for spintronics

全球数据中心网络为我们提供了免费获取新闻、社交媒体、信息和教育的能力，而这些都是我们认为理所当然的。 这些数据中心是互联网基础设施的一部分，它们是通过磁记录技术实现的，现在存储着世界上绝大多数的知识。然而，由于基本材料的限制，硅技术和硬盘驱动器在尺寸和速度方面数十年的指数级改进最近已经结束。 能源效率的提高将对数据中心的能源使用产生重要影响，数据中心已经消耗了北美总电力的约2%，以及手机，便携式电子产品和可穿戴电子产品的预测指数增长。作为手性磁性薄膜研究领域的世界领先团队之一，我的团队致力于为高能效、高速磁存储器的技术需求提供新的解决方案。与传统的存储介质不同，信息位存储在闪存驱动器上的微型晶体管中，或者存储在磁性硬盘驱动器中的大型旋转盘片上，手性磁性存储器将以纳米级圆柱形磁性纹理skyrmions存储信息，这些磁性纹理skyrmions自然形成于具有特定晶体对称性的磁性材料中。 Skyrmion存储器的信息编码速度比闪存快1000倍以上，并且由比传统磁畴小10万倍的电流移动。 在实际设备中使用skyrmion材料的主要障碍之一是大多数材料中的skyrmion仅在低于室温的温度下形成。 该提案旨在发现通过使用高通量真空沉积方法在远高于室温下产生skyrmions的新材料。 利用达尔豪西大学的组合溅射设备，可以在单个衬底上生长数百种合金成分。 X射线分析将能够快速筛选合金，以确定具有正确晶体对称性的成分，而电学测量将确定它们的磁有序温度。最好的候选材料将通过分子束外延以原子平面的单晶形式合成，磁性结构将通过电子和扫描探针显微镜在纳米级成像。通过调整合金成分，skyrmions的大小将被控制，以了解产生它们的基本相互作用。 就像气泡从一壶沸水的边缘成核一样，skyrmions从薄膜界面和边缘成核。 然后，我们可以通过选择在薄膜表面上存款的材料来控制这种成核。 然后，通过使用电流将Skyrmion推过纳米制造的电线，以开发新的Skyrmion磁存储器。

A global network of data centres powers the free access to news, social media, information and education that we take for granted. These data centres, which form part of the Internet's infrastructure, are made possible by magnetic recording technology that now stores the vast majority of the world's knowledge. However, both silicon technology and hard drives have recently seen the end of decades of exponential improvements in size and speed due to fundamental materials limitations. Improvements in energy efficiency will have important implications for the energy usage of data centres, which already consume approximately 2% of the total electricity in North America, as well as cell phones, portable electronics and the forecasted exponential growth of wearable electronics.******As one of the leading groups in the world in chiral magnetic thin film research, my group is positioned to yield new solutions to the technological demands of highly energy-efficient, high-speed magnetic memories. Unlike conventional visions of storage media where bits of information are stored in microfabricated transistors on flash drives, or on the large spinning platters in magnetic hard disk drives, chiral based magnetic memories will store information in nanoscale cylindrical magnetic textures skyrmions that naturally form in magnetic materials with particular crystal symmetries. Skyrmion memories would encode information over 1000 times faster than flash memory and be moved by currents 100,000 times smaller than conventional magnetic domains. One of the major obstacles to using skyrmion materials in practical devices is that skyrmions in most materials only form at temperatures below room temperature. This proposal seeks to discover new materials that produce skyrmions well above room temperature by using high-throughput vacuum deposition methods. Using combinatorial sputtering facilities at Dalhousie University, hundreds of alloy compositions can be grown on a single substrate. X-ray analysis will enable rapid screening of the alloys to identify those compositions with the right crystal symmetry, and electrical measurements will determine their magnetic ordering temperature. The best candidate materials will then be synthesized in atomically flat, single-crystal form by molecular beam epitaxy and the magnetic structures will be imaged at the nanoscale with electron and scanning probe microscopies.******By tuning the alloy composition, the size of the skyrmions will be controlled to understand the fundamental interactions that produce them. Just as bubbles nucleate from the edges of a pot of boiling water, skyrmions nucleate from film interfaces and edges. We can then control this nucleation by the choice of materials we deposit on the film surfaces. Skyrmions will then be pushed through nanofabricated wires by using electrical currents to develop new skyrmion magnetic memories.