Chemistry for 3D spintronics

自旋电子学在磁传感器领域价值数十亿美元，并在半导体行业（MRAM）迅速崛起。器件利用磁阻效应（磁化影响电流）和反向自旋传递力矩（自旋极化电流反向磁化）。自旋电子学需要几种磁性和非磁性材料接触，其长度尺度为几纳米。因此，它被薄膜技术的进步解锁，并发展为基于光刻的平面器件。然而，随着传感器和存储器的成熟，在功能或容量方面的局限性被识别出来。要求器件在三个方向上均能有效地感应磁场，这是平面技术难以实现的。对于存储器来说，增加面密度的竞争正在推动技术向3D方案发展，在这种方案中，大量的比特被存储在深度中。正是由于这一点，闪存最近才成为领头羊。我们将探索基于管和核壳管/线的3D自旋电子学的合成和物理构建块。自顶向下技术在定义这些方面存在局限性。相反，我们建议由两个化学小组和一个自旋电子最终用户组成一个跨学科的联盟。作为一个探索性项目，我们专注于为两种主要的自旋电子效应和应用类型提供一个构建块：单层（AMR）或核壳三层（GMR或TMR）的磁电阻，以传感器为背景。2. 在单层或金属/铁核-壳双层中进行自旋扭矩和自旋霍尔畴壁运动，并将3D赛道存储器作为潜在应用。在设备中，管将垂直嵌入介质中，在基于光刻的自下而上的孔或过孔中。在第一步中，我们将重点放在从模板中解放出来的单个对象上，并在表面上进行检查。合成包括用于模板的聚合物轨迹蚀刻膜和铝阳极化，用于核壳的金属和绝缘层的电（和化学）电镀和原子层沉积。物理测量包括电接触和磁电阻，结合磁显微镜。虽然孔隙中的电化学已经被用于制造阵列或垂直导线几十年了，但对单线和自旋电子学的研究才刚刚出现。关于磁管的报道屈指可数。该项目是探索性的，处于材料科学和自旋电子学的交叉路口。它是高风险/高增益，有希望的集成组件颠覆性概念。在短期内，它将为新物理学提供一个游乐场，预测将发生磁性与曲率和管的特定拓扑结构的相互作用。此外，另一个影响是促进化学家和自旋电子物理学家之间的联合工作，以解决物理方法面临限制的其他方面。考虑到审稿人的评论，该项目是一个重新提交。

Spintronics is worth billions in magnetic sensors, and is fast emerging in the semiconductor industry (MRAM). Devices use both effects of magnetoresistance (magnetization influencing electric current) and the reverse, spin-transfer torques (a spin-polarized current to reverse magnetization). Spintronics require several magnetic and non-magnetic materials in contact, with length scales a few nanometers. Thus, it was unlocked by progress in thin film technology, and developed as planar devices based on lithography.However, as sensors and memories are becoming mature, limitations in terms of functions or capacities are identified. Devices for sensing field efficiently equally in all three direction are required, which is difficult to achieve with planar technology. For memories, the competition for increased areal density is driving technology to 3D schemes, in which a large number of bits is stored in the depth. It is thanks to this that flash memory has become a leader recently.We will explore the synthesis and physics of building blocks for a 3D spintronics, based on tubes and core-shell tubes/wires. Top-down techniques face their limits to define these. Instead, we propose an interdisciplinary consortium with two chemistry groups and a spintronic end user. As an exploratory project, we focus on delivering a building block for the two major spintronic effects and type of application: 1. magneto-resistance in single (AMR) or core-shell trilayers (GMR or TMR), with sensors as background. 2. spin-torque and spin-Hall domain-wall motion in single or metal/ferro core-shell bilayers, with the 3D race-track memory as a potential application.In a device the tubes would be embedded vertically in a medium, in bottom-up pores or vias based on lithography. In this first step we focus on single objects freed from their template and inspected at a surface. Synthesis includes polymeric track-etched membranes and anodization of aluminum for templates, electro- (and electroless) plating and atomic layer deposition for both metal and insulating layers of the core-shell. Physical measurements consist of electrical contacting and magneto-resistance, combined with magnetic microscopy.While electrochemistry in pores has been used for decades to produce arrays or vertical wires, investigation on single wires, and spintronics in mind, is only emerging. Only a handful of reports exist on magnetic tubes. The project is exploratory, at the cross-roads of material science and spintronics. It is high risk/high-gain, promising disruptive concepts for integrated components. In the shorter run, it will provide a playground for new physics, predicted to occur with interplay of magnetism with curvature and the specific topology of tubes. Besides, another impact is to foster joint work between chemists and spintronic physicists, to address other aspects where physical methods face limits.The project is a resubmission, taking into account reviewers' comments.