外尔半金属/垂直磁各向异性薄膜异质结构的制备及其自旋轨道转矩研究

In this project, we are planning to introduce and combine Weyl semimetal into the research field of spin-orbit electronics, to optimize and obtain the Weyl semimetal/magnetic heterostructure with perpendicular magnetic anisotropy. By using Weyl semimetal’s (1) high charge-spin efficiency, which is comparable with that of topological insulators and larger than that of heavy metals, (2) good conductive ability, and (3) novel out-of-plane anti-damping torque etc., the perpendicular magnetic moment can be driven more efficiently and the critical switching current density can be much reduced. By understanding of the physical properties such as charge-spin conversion efficiency and spin-orbit torque, studies of the process of spin-orbit torque driven perpendicular magnetization switching under zero or small magnetic field, we will explain and clarify the driven-magnetization mechanism by various spin torques. This project is extremely important for the research and development of spintronics devices with lower energy consumption, especially field free spin-orbit torque magnetic random access memory. The research of this project is of great significance in terms of both science and application.

本项目拟将外尔半金属引入自旋轨道电子学研究，优化制备具有垂直磁各向异性的外尔半金属/垂直磁各向异性薄膜异质结构。利用外尔半金属(1)与拓扑绝缘体可比拟且比重金属更大的电荷-自旋转换效率、(2)较好的电导特性、(3)新奇的垂直膜面方向的抗阻尼力矩等特性，以此可更高效驱动垂直磁矩进而有效降低临界翻转电流密度。通过理解电流-自旋转换效率和自旋轨道转矩等物理性质，研究零磁场或小磁场下基于自旋轨道转矩效应电流驱动垂直磁化翻转的过程，阐明其各类自旋力矩对于磁矩翻转驱动的物理机制。本项目对于自旋电子学低功耗器件尤其全电学驱动磁化翻转的自旋轨道力矩型磁随机存储器的研究和开发，具有非常重要的科学和应用价值。

本项目将外尔半金属引入自旋轨道电子学研究，优化生长并成功制备具有垂直磁各向异性的外尔半金属垂直磁各向异性薄膜(WTe2/CoTb)异质结构。利用外尔半金属拓扑绝缘体可比拟且比重金属更大的电荷-自旋转换效率及较好的电导特性，实现了更高效驱动垂直磁矩进而有效降低临界翻转电流密度。通过理解电流-自旋转换效率和自旋轨道转矩等物理性质，研究零磁场或小磁场下基于自旋轨道转矩效应电流驱动垂直磁化翻转的过程。本项目对于自旋电子学低功耗器件尤其全电学驱动磁化翻转的自旋轨道力矩型磁随机存储器的研究和开发，具有一定的科学和应用价值。项目执行三年来，我们按照项目计划围绕“外尔半金属/垂直磁各向异性薄膜异质结构的制备及其自旋轨道转矩研究”取得一系列研究成果，共计完成学术论文12篇，获得授权发明专利2项，培养了8名硕士毕业研究生，达到并完成项目预期目标。