Hybrid three-dimensional solitons for applications

混合三维孤子的应用

• 批准号: 403502830
• 负责人: Dr. Nikolai S. Kiselev, Ph.D.
• 金额: --
• 依托单位: PGI-1 / IAS-1: Quanten-Theorie der Materialien
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/403502830?language=en
• 关键词: Hybrid; three; dimensional; solitons; applications

Chiral magnets (ChMs) comprise a distinct class of magnetic crystals with unique properties, which are significantly distinct from those of other magnetically ordered systems such as common ferro- or antiferromagnets. This class of magnetic crystals includes different Si- and Ge-based alloys, such as MnSi, FeGe and β-Mn-type Co-Zn-Mn alloys. Nanostructured thin films and stripes of such ChMs have properties that are different from those of bulk crystals. The reduced dimensionalities of such systems provide nontrivial mechanisms for the stabilization of particle-like states that are known as magnetic skyrmions and are promising objects for applications in spintronics. Recently, we reported that the presence of natural geometrical confinement and free boundaries in such crystals is responsible for the stabilization of other particle-like objects – chiral bobbers (ChBs). Such hybrid particles have smooth magnetization vector fields and magnetic singularities – Bloch points that are located a certain distance from the surface of the crystal. As a result of the nontrivial spin textures and compact sizes of ChBs, they are interesting objects for fundamental research and practical applications. The aim of the proposed project is a theoretical and experimental study of the static and dynamic properties of such hybrid solitons: their thermal stability, pairwise interaction, spectrum of excitations in an AC magnetic field, mobility under an electric current, behavior in the presence of a thermal gradient and interactions with spin waves. Theoretical descriptions will be based on both commonly used approaches of continuum micromagnetic theory and atomistic spin-lattice models. Direct energy minimization, spin dynamics driven by electric currents and external magnetic fields, Monte Carlo simulations and calculations of energy barriers, as well as other methods implemented in the software developed in our group, will be used to construct magnetic phase diagrams, dispersion curves, energy barriers, velocity dependencies for ChBs, etc.The theoretical work will be supported by high-resolution quantitative measurements of the magnetic fields of skyrmions and ChBs performed using off-axis electron holography (EH) and Lorentz imaging in the transmission electron microscope (TEM), allowing quantitative comparisons of theoretically predicted effects with experimental observations and vice versa. TEM experiments will be performed in the Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C; www.er-c.org), which is a national user centre for electron microscopy and a leading institute in the development and application of advanced electron microscopy methodologies.

手性磁体（ChM）包括具有独特性质的独特类别的磁性晶体，其显著不同于其他磁性有序系统（例如常见的铁磁体或反铁磁体）的磁性晶体。这类磁性晶体包括不同的Si基和Ge基合金，例如MnSi、FeGe和β-Mn型Co-Zn-Mn合金。 这种ChM的纳米结构薄膜和条带具有不同于块状晶体的性质。这种系统的降维提供了非平凡的机制，用于稳定被称为磁skyrmions的粒子状状态，并且是自旋电子学应用的有前途的对象。最近，我们报道，在这样的晶体中的自然几何约束和自由边界的存在是负责其他颗粒状物体的稳定-手性bobbers（ChB）。这种混合粒子具有平滑的磁化矢量场和磁奇点-位于距离晶体表面一定距离处的布洛赫点。 由于ChB的非平凡自旋纹理和紧凑的尺寸，它们是基础研究和实际应用的有趣对象。该项目的目的是对这种混合孤子的静态和动态特性进行理论和实验研究：它们的热稳定性、成对相互作用、交流磁场中的激发谱、电流下的迁移率、热梯度存在下的行为以及与自旋波的相互作用。理论描述将基于连续微磁理论和原子自旋晶格模型的常用方法。直接能量最小化，由电流和外部磁场驱动的自旋动力学，Monte Carlo模拟和能垒计算，以及在我们小组开发的软件中实现的其他方法，将用于构建磁相图，色散曲线，能垒，ChB的速度依赖性，理论工作将得到离轴电子全息（EH）对Skyrmions和ChB磁场的高分辨率定量测量的支持。和洛伦兹成像在透射电子显微镜（TEM），允许定量比较理论预测的影响与实验观察，反之亦然。TEM实验将在Ernst Ruska电子显微镜和光谱学中心（ER-C; www.example.com）进行，该中心是电子显微镜的国家用户中心，也是先进电子显微镜方法开发和应用的领先研究所。