Element specific spin dynamics of nano- and heterostructues studied with ultimate spatial resolution

以最终空间分辨率研究纳米和异质结构的元素特定自旋动力学

• 批准号: 321560838
• 负责人: Dr. Katharina Ollefs
• 金额: --
• 依托单位: Institut für Halbleiter- und Festkörperphysik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/321560838?language=en
• 关键词: Element; specific; spin; dynamics; nano

The aim of this proposal is to carry out a systematic investigation of the dynamic magnetic properties of individual magnetic micro- and nano-objects in a complex magnetic environment utilizing a novel experimental tool, which the applicants jointly developed with the beamline staff of the Stanford Synchrotron Radiation Laboratory (SSRL). This rather unique novel instrument combines element specific investigation of the magnetic properties based on X-ray magnetic circular dichoism (XMCD) with the lateral spatial resolution of nominally 35 nm of the scanning transmission x-ray microscope (STXM) as well as a time-resolved detection scheme down to 17 ps allowing to study time-resolved transversal x-ray detected ferromagnetic resonance (XFMR) with spatial resolution. The microwave excitation is based on lithographically fabricated micro-resonators on SiN membranes into which the magnetic micro- or nano-object in question will be placed. The use of these microresonators provides the unique opportunity to simultaneously investigate the conventional FMR signal which averages over the magnetic ensemble and the space resolved XFMR response of each individual nano constituent. We aim at pursuing the following range of experiments:1. spatial imaging and time resolved phase information of uniform and non-uniform spinwave excitations in micro- and nanostripes where the excitation modes are modified by the shape of the structures or by local stray-fields generated by adjacent ferromagnetic structures. These local fields can be used to enhance or suppress local excitations. Planned materials for the structures will be Co as hard and Permalloy (Py) as soft magnetic material.2. investigations of local dynamic magnetic properties of individual nanoparticles under the influence of magnetic coupling or local stray fields in an ensemble using individual Fe or Fe oxide nanoparticles. The magnetic excitation states can be tailored by arranging the nano particles in different geometries and/or number backed by micro magnetic simulations. 3. direct imaging of spin currents in a non-magnetic material generated by spin-pumping in hetero structures utilizing the element specificity, space- and time-resolution of the STXM-FMR. A Py microstripe on top of a low spin-orbit coupling material like ZnO or Al shall be driven into FMR and the spatial distribution and relative phase of the generated spin current will be imaged.

该提案的目的是利用一种新的实验工具，对复杂磁环境中单个磁性微米和纳米物体的动态磁特性进行系统研究，该实验工具是申请人与斯坦福大学同步辐射实验室（SSRL）的光束线工作人员联合开发的。这种相当独特的新型仪器结合了基于X射线磁圆二向性（XMCD）的磁特性的元素特定调查与扫描透射X射线显微镜（STXM）的标称35 nm的横向空间分辨率以及时间分辨检测方案下降到17 ps，允许研究时间分辨横向X射线检测铁磁共振（XFMR）与空间分辨率。微波激发是基于SiN膜上的光刻制造的微谐振器，所讨论的磁性微米或纳米物体将被放置在该微谐振器中。这些微谐振器的使用提供了独特的机会，同时调查传统的FMR信号，平均超过磁合奏和空间分辨XFMR响应的每个单独的纳米成分。我们的目标是追求以下范围的实验：1。在微米和纳米带中的均匀和非均匀自旋波激发的空间成像和时间分辨相位信息，其中激发模式由结构的形状或由相邻铁磁结构产生的局部杂散场修改。这些局部场可用于增强或抑制局部激励。结构的计划材料将是钴作为硬磁材料和坡莫合金（Py）作为软磁材料。在使用单个Fe或Fe氧化物纳米颗粒的总体中，在磁耦合或局部杂散场的影响下，对单个纳米颗粒的局部动态磁性进行研究。磁激发状态可以通过以不同的几何形状和/或数量排列纳米颗粒来定制，这些纳米颗粒由微磁模拟支持。3.利用STXM-FMR的元件特异性、空间和时间分辨率，对通过异质结构中的自旋泵浦产生的非磁性材料中的自旋电流进行直接成像。在低自旋-轨道耦合材料（如ZnO或Al）的顶部上的Py微条纹将被驱动到FMR中，并且将对所产生的自旋电流的空间分布和相对相位进行成像。