SPINCURRENT: Domain Walls and Spin-Polarised Currents

在磁性材料中产生、操纵和检测自旋极化电流的能力导致了现在新兴的自旋电子学领域的活动爆炸，在自旋电子学领域，电子的自旋和电荷被用来处理和存储信息。关于自旋电子学的前景和未来影响的文章在普通读者杂志上很常见，如《新科学家》、《科学美国人》、《IEEE光谱》、《今日物理》和《物理世界》。科学影响的证据可以在《自然》、《科学》和《物理评论快报》等期刊上的大量研究文章中找到（1988年PRL报告发现巨磁阻是有史以来第六大被引用最多的），而IBM、日立、西门子、飞思卡尔等公司的大规模投资，希捷等在自旋电子学基础研究上的巨大收入（每年数十亿美元）他们已经从利用基本巨磁电阻（GMR）自旋电子效应的早期设备（如硬盘自旋阀磁头）中获得了收益，并有望从未来的技术突破中获得收入。利用自旋的器件提供了更高速度、更低功耗和更密集缩放的操作，并提供了全新功能的机会，例如非易失性数据存储或可重新配置的逻辑门。畴壁是一种天然存在的磁性纳米结构，在这项提案中，我们正在寻求资金，以开展一项广泛的研究，研究纳米级磁性器件中畴壁与自旋极化电流的相互作用。这两个物体之间存在相互关系：一方面，畴壁可能会导致自旋极化电子在穿过它时的额外（或减少）散射，当磁化饱和到单畴状态并且移除畴壁时，会引起电阻的变化。另一方面，当电子经历这种散射时，它们的波矢量和/或自旋状态将改变，并且相关联的线动量或角动量的量被转移到壁，从而产生力或扭矩。这可能导致电流诱导的室壁运动。这两种效应，以及被极大的科学兴趣，是实质性的技术承诺。

The ability to generate, manipulate and detect spin-polarised electrical currents in magnetic materials has resulted in an explosion of activity in the now burgeoning field of spintronics, where the spin, as well as the charge, of the electron is used to process and store information. Articles about the promise and future impact of spintronics are commonplace in general audience magazines such as New Scientist, Scientific American, IEEE Spectrum, Physics Today, and Physics World. Evidence for the scientific impact is found in the high number of research articles in journals such as Nature, Science and Physical Review Letters (the 1988 PRL reporting the discovery of giant magnetoresistance is the sixth most highly cited of all time), whilst the massive investment of companies such as IBM, Hitachi, Siemens, Freescale, Seagate etc. in spintronics-based research is based on the huge revenue (billions of $ p.a.) that they are already reaping from early devices exploiting the basic Giant Magnetoresistance (GMR) spintronic effect such as hard disc spin-valve heads, and the revenue that is expected from future technological breakthroughs. Devices taking advantage of spin offer operation at higher speeds, lower power, and denser scaling, as well as giving the opportunity of entirely new functionality, such as non-volatile data storage or reconfigurable logic gates . A domain wall is a naturally occurring magnetic nanostructure and in this proposal we are seeking funding to launch a wide ranging study of the interactions of domain walls in nanoscale magnetic devices with spin-polarised currents. There is a reciprocal relationship between these two objects: on the one hand, the domain wall may cause additional (or reduced) scattering of the spin-polarised electrons as they traverse it, giving rise to a change in resistance when the magnetisation is saturated to a single domain state and the wall is removed. On the other, as the electrons undergo this scattering their wavevector and/or spin state will change and the associated amount of linear or angular momentum is transferred to the wall, giving rise to a force or torque. This can cause current-induced wall motion. Both of these effects, as well as being of great scientific interest, are of substantial technological promise.