Hybrid three-dimensional solitons for applications

手性磁体（ChMs）是一类具有独特性质的磁性晶体，与普通铁磁体或反铁磁体等其他磁性有序系统明显不同。这类磁性晶体包括不同的硅基和锗基合金，如MnSi、FeGe和β- mn型Co-Zn-Mn合金。这种chm的纳米结构薄膜和条纹具有不同于块状晶体的特性。这种系统的降维特性为类粒子态的稳定提供了重要的机制，这些类粒子态被称为磁skyrmions，是自旋电子学中很有前途的应用对象。最近，我们报道了这种晶体中自然几何约束和自由边界的存在是其他类粒子物体-手性跳子（ChBs）稳定的原因。这种混合粒子具有平滑的磁化矢量场和磁奇点——布洛赫点，它们位于离晶体表面一定距离的地方。由于chb的非平凡自旋结构和紧凑的尺寸，它们是基础研究和实际应用的有趣对象。该计划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两种常用方法。直接能量最小化、由电流和外部磁场驱动的自旋动力学、能量势垒的蒙特卡罗模拟和计算，以及我们小组开发的软件中实现的其他方法，将用于构建chb的磁相图、色散曲线、能量势垒、速度依赖关系。理论工作将通过离轴电子全息（EH）和透射电子显微镜（TEM）中的洛伦兹成像（Lorentz imaging）对skyrmions和ChBs的磁场进行高分辨率定量测量来支持，从而使理论预测效应与实验观察结果进行定量比较，反之亦然。透射电镜实验将在恩斯特·鲁斯卡电子显微镜和光谱学中心（ER-C; www.er-c.org）进行，该中心是电子显微镜的国家用户中心，也是开发和应用先进电子显微镜方法的领先研究所。

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.