Synthetic Antiferromagnetic Skyrmions

合成反铁磁斯格明子

基本信息

批准号：
EP/T006803/1
负责人：
Christopher Marrows
金额：
$ 103.93万
依托单位：
University of Leeds
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2020
资助国家：
英国
起止时间：
2020 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FT006803%2F1
关键词：
Synthetic Antiferromagnetic Skyrmions

项目摘要

In this project we will stabilise small circular magnetic domains called skyrmions in chiral synthetic antiferromagnetic multilayers and study their current-driven dynamics. The project is based on two recent breakthroughs by our groups: our being able to stabilise skyrmions as a topologically protected structure (making them resistant to annihilation) in a suitably designed single chiral perpendicularly magnetised layer, and being able to move coupled topological defects (domain walls) at low current density in a simple in-plane magnetised synthetic antiferromagnet.Whilst conventional skyrmions are interesting candidates for a variety of novel information storage and processing devices that offer the prospect of very low power operation, they are expected to move slowly at small sizes due to topological damping and are diverted at an angle to their current drive direction by the Magnus forces that lead to a skyrmion Hall effect. To realise their potential, we need to establish the optimal multilayer structure to support synthetic antiferromagnetic skyrmions that are small, highly mobile, and move in the direction of an electrical current drive. We need to find a reliable nucleation method to that can create synthetic antiferromagnetic skyrmions in a controlled manner for further study. We need to know how make synthetic antiferromagnetic skyrmions respond directly to spin current drives by balancing the Magnus forces on the two component skyrmions to reduce the skyrmion Hall angle to zero. Finally, we need to learn how to exploit the expected suppression of topological damping in order to move the synthetic antiferromagnetic skyrmions move at velocities far higher, and at smaller sizes, than for conventional skyrmions. In this project we will prepare chiral magnetic multilayers that support synthetic antiferromagnetic skyrmions, image the skyrmion structures, and fabricate nanoscale devices in which we can measure current-driven skyrmion dynamics. We will combine our expertise with synthetic antiferromagnet multilayers with our proven ability to induce strong Dzyaloshinskii-Moriya interactions at interfaces to combine two coupled skyrmions with opposite polarity and chirality into a synthetic antiferromagnetic skyrmion that can be stabilised at room temperature, with their structure and motion under field imaged using state-of-the-art microscopy techniques. Next, we will study the nucleation of synthetic antiferromagnetic skyrmions at randomly occurring and deliberately introduced defects due to the application of stimuli including pulses of magnetic field or electrical current. We will then prepare skyrmion racetracks along which synthetic antiferromagnetic skyrmions can be propelled using current-driven torques from this optimised multilayer stack and image the skyrmion motion at moderate current densities in order to measure the skyrmion Hall angle and find the conditions when it is zero. We will go on to increase the current densities to seek high velocity skyrmion motion exploiting the suppression of topological damping that arises between coupled topological defects in synthetic antiferromagnets.The results we shall obtain will not only lead to high impact publications and conference presentations by shedding light on the possibilities offered by this novel combination of materials, but also develop potentially valuable knowhow in the field of spintronics based on synthetic antiferromagnetic skyrmions for technological applications.

在这个项目中，我们将稳定手性合成反铁磁多层中称为斯格明子的小圆形磁畴，并研究它们的电流驱动动力学。该项目基于我们小组最近的两项突破：我们能够在适当设计的单个手性垂直磁化层中稳定斯格明子作为拓扑保护结构（使它们抵抗湮灭），并且能够移动耦合拓扑缺陷（域壁）在简单的面内磁化合成反铁磁体中以低电流密度。虽然传统的斯格明子是各种新颖的信息存储和处理设备的有趣候选者，这些设备提供了非常低功耗操作的前景，但它们预计由于拓扑阻尼而以小尺寸缓慢移动，并通过导致斯格明子霍尔效应的马格努斯力以与当前驱动方向成一定角度的方式转向。为了发挥它们的潜力，我们需要建立最佳的多层结构来支持合成反铁磁斯格明子，这些斯格明子体积小、移动性高，并且沿着电流驱动的方向移动。我们需要找到一种可靠的成核方法，能够以受控方式产生合成反铁磁斯格明子，以供进一步研究。我们需要知道如何通过平衡两个分量斯格明子上的马格努斯力来将斯格明子霍尔角减小到零，从而使合成反铁磁斯格明子直接响应自旋电流驱动。最后，我们需要学习如何利用拓扑阻尼的预期抑制，以使合成反铁磁斯格明子以比传统斯格明子更高的速度和更小的尺寸移动。在这个项目中，我们将制备支持合成反铁磁斯格明子的手性磁性多层膜，对斯格明子结构进行成像，并制造可以测量电流驱动的斯格明子动力学的纳米级器件。我们将把我们的专业知识与合成反铁磁体多层膜结合起来，与我们在界面处诱导强 Dzyaloshinskii-Moriya 相互作用的能力相结合，将两个具有相反极性和手性的耦合斯格明子结合成合成反铁磁斯格明子，该合成反铁磁斯格明子可以在室温下稳定，其结构和运动使用最先进的显微镜技术进行现场成像。接下来，我们将研究由于施加磁场或电流脉冲等刺激而随机发生和故意引入的缺陷中合成反铁磁斯格明子的成核。然后，我们将准备斯格明子跑道，沿着该跑道，可以使用来自该优化的多层堆栈的电流驱动扭矩来推动合成反铁磁斯格明子，并在中等电流密度下对斯格明子运动进行成像，以便测量斯格明子霍尔角并找到其为零时的条件。我们将继续增加电流密度，以利用合成反铁磁体中耦合拓扑缺陷之间产生的拓扑阻尼的抑制来寻求高速斯格明子运动。我们将获得的结果不仅会带来高影响力的出版物和会议演讲。不仅研究这种新颖的材料组合所提供的可能性，而且还开发基于合成反铁磁斯格明子的自旋电子学领域潜在的有价值的专业知识，以用于技术应用。

项目成果

期刊论文数量（7）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Breathing modes of skyrmion strings in a synthetic antiferromagnet multilayer

DOI：
10.1063/5.0142772
发表时间：
2021-12
期刊：
Journal of Applied Physics
影响因子：
3.2
作者：
Christopher E. A. Barker;E. Haltz;T. Moore;C. Marrows
通讯作者：
Christopher E. A. Barker;E. Haltz;T. Moore;C. Marrows

Perspective on skyrmion spintronics

DOI：
10.1063/5.0072735
发表时间：
2021-12-20
期刊：
APPLIED PHYSICS LETTERS
影响因子：
4
作者：
Marrows, C. H.;Zeissler, K.
通讯作者：
Zeissler, K.

Domain wall motion at low current density in a synthetic antiferromagnet nanowire

DOI：
10.1088/1361-6463/ace6b4
发表时间：
2022-05
期刊：
Journal of Physics D: Applied Physics
影响因子：
0
作者：
Christopher E A Barker;S. Finizio;E. Haltz;S. Mayr;P. Shepley;T. Moore;G. Burnell;J. Raabe;C. Marrows
通讯作者：
Christopher E A Barker;S. Finizio;E. Haltz;S. Mayr;P. Shepley;T. Moore;G. Burnell;J. Raabe;C. Marrows

On-axis sputtering fabrication of Tm3Fe5O12 film with perpendicular magnetic anisotropy

垂直磁各向异性Tm3Fe5O12薄膜的同轴溅射制备