Spin-orbitronics in epitaxial CuMnSb/NiMnSb half-Heusler heterostructures

外延 CuMnSb/NiMnSb 半赫斯勒异质结构中的自旋轨道电子学

• 批准号: 397861849
• 负责人: Dr. Johannes Kleinlein
• 金额: --
• 依托单位: Lehrstuhl für Experimentelle Physik III
• 依托单位国家: 德国
• 项目类别: Research Grants
• 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/397861849?language=en
• 关键词: Spin; orbitronics; epitaxial; CuMnSb; NiMnSb

In this project spin-orbit torque (SOT) related effects in heterostructures comprised of the half-Heusler alloys CuMnSb (antiferromagnetic, AFM) and NiMnSb (ferromagnetic, FM) will be investigated. Such spin-orbit torques originate from charge currents that get spin polarized when passing through materials with strong spin-orbit coupling (SOC). For ferromagnetic or antiferromagnetic SOC materials, this spin polarization interacts locally with the magnetic moments. This field of experiments that takes advantage ofthe spin-orbit torque is recently called “spin-orbitronics”.As a first step a molecular beam epitaxy growth process for high crystal quality CuMnSb will be further developed and optimized. Single layers of CuMnSb will be grown on InAs (001) substrates; heterostructures of CuMnSb combined with NiMnSb will be grown on InP (001) substrates. As grown samples will be mainly characterized by X-Ray diffraction for crystal properties and quality, as well as by SQUID to determine magnetic parameters. In NiMnSb/CuMnSb heterostructures, the exchange coupling between the FM and the AFM will be of special interest. For electrical characterization a standard hall-bar geometry will be patterned using optical lithography. Here, we material parameters will be determined, such as resistivity or Hall-constant. Several experiments that make use of the spin-orbit torque will be conducted: 1) Single layers of epitaxial CuMnSb will be used to demonstrate switching of the magnetic sublattice of the AFM. Via the anisotropic magnetoresistance (AMR), we will be able to probe the orientation of the magneticsublattice. 2) In a second set of devices, we will combine AFM CuMnSb and ferromagnetic films deposited by sputtering. Here, our main goal is to switch the magnetization of the FM using the spin-orbit torque created in the AFM and the exchange coupling. 3) For the final devices, fully epitaxial NiMnSb/CuMnSb heterostructures will be used to fabricate tunneling anisotropic magnetoresistance devices. These devicesoffer the possibility to investigate magnetic characteristics of the CuMnSb in a magnetotransport experiment by making use of the exchange spring effect.

在这个项目中，我们将研究半Heusler合金CuMnSb(反铁磁，AFM)和NiMnSb(铁磁，FM)组成的异质结中与自旋轨道扭矩(SOT)相关的效应。这种自旋-轨道扭矩源于电荷电流，当通过具有强烈自旋-轨道耦合(SOC)的材料时，电荷电流会产生自旋极化。对于铁磁或反铁磁SOC材料，这种自旋极化与磁矩局部相互作用。这个利用自旋-轨道扭矩的实验领域最近被称为“自旋-轨道电子学”。作为第一步，我们将进一步开发和优化高质量CuMnSb的分子束外延生长工艺。在InAs(001)衬底上生长单层CuMnSb，在InP(001)衬底上生长CuMnSb与NiMnSb结合的异质结。生长的样品将主要通过X射线衍射来表征晶体的性质和质量，以及通过SQUID来确定磁性参数。在NiMnSb/CuMnSb异质结中，FM和AFM之间的交换耦合将引起人们的特别关注。对于电学特性，将使用光学光刻技术对标准的霍尔杆几何形状进行图案化。在这里，我们将确定材料参数，如电阻率或霍尔常数。将进行几个利用自旋轨道力矩的实验：1)将使用单层外延CuMnSb来演示AFM的磁亚晶格的切换。通过各向异性磁阻(AMR)，我们将能够探测到磁亚晶格的取向。2)在第二套装置中，我们将AFM CuMnSb与溅射沉积的铁磁性薄膜相结合。在这里，我们的主要目标是利用原子力显微镜中产生的自旋轨道扭矩和交换耦合来切换FM的磁化。3)对于最终器件，将采用全外延NiMnSb/CuMnSb异质结来制备隧道各向异性磁阻器件。这些装置为利用交换弹簧效应在磁输运实验中研究CuMnSb的磁特性提供了可能。