Mesoscopic topological spin textures, spin and topological Hall effect in magnetic thin films and heterostructures

量子材料中的拓扑自旋织构沿着相关的输运特征对于下一代自旋电子学应用具有重要意义。最重要的现象是拓扑霍尔效应（THE），它对每个拓扑纹理都有不同的签名。一般来说，THE是由磁织构的大小和电荷载流子的耦合强度，它。在本项目中，我们将研究拓扑自旋现象介观系统，如薄膜，异质结界面和微米尺寸的结构从单晶。 我们打算通过材料设计和器件的尺寸来定制磁自旋织构。我们将探索新的Heusler和相关的Mn基化合物与手性自旋纹理。通过在不同温度和外磁场和电场下的横向和纵向输运测量来检测拓扑特征。在第一部分中，我们将从PtMnGa，MnBi，Nd_2Fe_（14）B，Dy_2Fe_（14）B，手性化合物FePtMo_（3）N和铁磁货车德瓦耳斯半金属Fe_（3）GeTe_2的硬磁相制备微米尺寸的结构。我们将通过输运测量来检测拓扑磁激发。此外，我们的合作者将把运输响应与真实空间成像技术相结合。在第二部分中，我们计划研究高质量的外延薄膜，异质结构和界面。我们将探索：（i）具有D2 d对称性的新Heusler化合物，如Mn 2 IrSn和Mn 2 PtIn，理论上预测为反kyrmions的宿主。我们的目标是找到一个完全补偿的亚铁磁或反铁磁Heusler材料与反铁磁skyrmions。(ii)六方晶系PtMnGa（Al）和MnBi等新化合物。(iii)不同量子材料的组合，例如，拓扑绝缘体或半金属/（反）Skyrmion、铁电/（反）Skyrmion。我们的目标是生长具有高质量界面的异质结构，我们希望在那里找到新的特性，大自旋霍尔效应和新的先进功能。

Topological spin textures in quantum materials are of great interest, along with the associated transport signatures, for next-generation spintronic applications. The most important phenomenon is the topological Hall effect (THE), which has a distinct signature for each topological texture. Generally, the THE is determined by the size of the magnetic texture and the coupling strength of the charge carriers to it.Within the present project, we will study topological spin phenomena in mesoscopic systems, such as thin films, heterostructures-interfaces and micron-sized structures from single crystals. We intend to tailor the magnetic spin textures by materials design and the dimensions of the device. We will be exploring novel Heusler and related Mn-based compounds with chiral spin textures. The topological features will be detected through transverse and longitudinal transport measurements at different temperatures and external magnetic and electric fields.The work plan is divided into two parts. In the first part, we will prepare micron-sized structures from hard magnetic phases of PtMnGa, MnBi, Nd2Fe14B, Dy2Fe14B, the chiral compound FePtMo3N and the ferromagnetic van der Waals semimetal Fe3GeTe2. We will detect the topological magnetic excitations through transport measurements. Additionally, the transport responses will be combined with real-space imaging techniques by our collaborators. In the second part, we plan to investigate high-quality epitaxial thin films, heterostructures and interfaces. We will be exploring: (i) New Heusler compounds with D2d symmetry, such as Mn2IrSn and Mn2PtIn, theoretically predicted to host antiskyrmions. The goal is to find a fully compensated ferrimagnet or antiferromagnetic Heusler material with antiferromagnetic skyrmions. (ii) New compounds such as the hexagonal PtMnGa(Al) and MnBi. (iii) The combination of different quantum materials, e.g., topological insulator or semimetal / (anti)skyrmion, ferroelectric / (anti)skyrmion. We aim to grow heterostructures with high quality interfaces where we expect to find novel properties, large spin Hall effect, and new advanced functionalities.