Spin-Polarised Tunnelling in Magnetic Nanostructures: A UK-China Collaboration

磁隧道结(MTJ)是典型的自旋电子器件，它通过自旋极化来控制电流的流动，然后当它以量子力学的方式穿过纳米厚的绝缘势垒时进行分析。它们构成了当前两种商用自旋电子技术的功能核心，即硬盘驱动器的读回头和MRAM中的位单元存储元件。因此，它们是当前最重要的自旋电子技术。然而，基于氧化铝和氧化镁屏障的主流MTJ材料系统已经在这些应用中实现了商业化。下一代基于MTJ的设备需要新的方法。这项提议建立在利兹大学和位于北京的中国科学院(CAS)物理研究所磁学国家重点实验室之间日益增长和富有成效的合作的基础上。这两个实验室都是各自国家研究MTJ的主要实验室。在材料生长、纳米制造、表征和测量方面具有互补优势。自2005年作为EPSRC/外交部访问中国的一部分举行第一次会议以来，两个小组已经开始合作，到目前为止，双方各进行了两次互访，第一批联合出版物开始出现。在这里，我们提出了一个联合研究计划，针对MTJ的新材料和设备架构，提供了改进和新功能的前景。我们的建议有三个主要研究主题。前两种是基于用于隧道势垒和潜在高度自旋极化电极的新型无机材料，以及有机势垒材料、自组装分子层和少层石墨烯薄片。最后一项是开发一种基于颗粒双势垒隧道结的门控自旋极化单电子晶体管，这种晶体管完全可以用传统的平面工艺制造。之所以选择这些主题，是因为我们已经确定，新的合作努力将我们目前研究活动的各个领域联系起来并建立起来，从而本身就能带来新的科学成果，并为我们两个团队之间最成功的人提供长期可持续合作的前景。支持这个项目将使我们能够巩固我们新生的合作关系，并为双方带来互惠互利。它不仅将使我们能够完成两个团队都无法单独完成的科学工作，而且还为两个实验室的年轻研究人员提供了一个独特的培训机会。

Magnetic tunnel junctions (MTJs) are the prototypical spintronic device, controlling the flow of an electrical current by spin-polarising and subsequently analysing it as it tunnels quantum mechanically through a nanometer thick insulating barrier. They form the functional heart of the two current commercial spintronic technologies, the read-back head of a hard disk drive, and the bit cell storage element in MRAM. As such they are the most important current spintronic technology. Nevertheless, the mainstream MTJ materials systems, based on alumina and magnesium oxide barriers, are already commercialised in these applications. New approaches are needed for the next generation of MTJ-based devices.This proposal builds on a growing and productive collaboration between the University of Leeds, and the State Key Laboratory for Magnetism at the Institute of Physics, Chinese Academy of Science (CAS) in Beijing. Both are leading laboratories in their respective countries for the study of MTJs. and have complementary strengths in materials growth, nanofabrication, characterisation and measurement. Since first meeting as part of the EPSRC/Foreign Office mission to China in 2005, the two groups have begun collaborating with two exchange visits on each side to date and the first joint publications starting to emerge. Here we propose a joint programme of research addressing novel materials and device architectures for MTJs that offer the prospect of improved and new functionalities.Our proposal has three main research themes. The first two are based around novel inorganic materials for tunnelling barriers and potentially highly spin-polarised electrodes, and organic barrier materials, self-assembled molecular layers and few-layer graphene flakes. The last is to develop a gated spin-polarised single electron transistor, based on granular double barrier tunnels junctions, which can be fabricated entirely using conventional planar processes. These topics have been chosen since we have identified them as ones where new collaborative efforts that link and build on areas of our current portfolios of research activity to both bring about new scientific results in their own right, as well as offering the prospect of longer term sustainable collaboration between our two groups for the most successful. Supporting this project will allow us to cement our nascent collaborative relationship, and bring mutual benefit to both groups. Not only will it allow us to do science that neither group can do alone, but it offers a unique training opportunity for the young researchers of both laboratories.