导电氧化铋薄膜的逆自旋霍尔效应-中国材料进展

文章信息/Info

Author(s):: WANG Mengyi; QIU Zhiyong; (Key Laboratory of Energy Materials and Devices (Liaoning Province), Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Ministry of Education, School of Materials Science and Engineering, Dalian University of Technology, Dalian 116000, China)

Keywords:: bismuth oxide; conductive oxide; inverse spin Hall effect; spin Hall angle; spin diffusion length; spin pumping

摘要:: 自旋霍尔效应及其逆效应作为自旋电子学中实现自旋电荷转换的核心物理效应，对纯自旋流的产生、探测有着重要的应用价值，是自旋电子器件开发与应用的关键技术节点。对高自旋电荷转换效率材料体系的探索与开发是该领域的核心课题。以导电氧化铋薄膜为对象，研究其中的逆自旋霍尔效应。采用交流磁控溅射系统，使用氧化铋陶瓷靶制备了不同厚度的导电氧化铋薄膜，并与坡莫合金薄膜构成铁磁/非磁双层自旋泵浦器件，在该器件中首次观测并确认了导电氧化铋薄膜中逆自旋霍尔效应所对应的电压信号。通过逆自旋霍尔电压对氧化铋薄膜厚度的依存关系，定量地估算了氧化铋薄膜的自旋霍尔角及自旋扩散长度。通过提出一种新的具备可观测逆自旋霍尔效应的材料体系，不仅拓展了自旋电子材料的选择空间，也为新型自旋电子器件的设计和应用提供了思路。

Abstract:: The direct and inverse spin Hall effect is the key effect for spin-charge conversion in spintronics, which plays a vital role in the generation and detection of pure spin currents. It is a core issue to develop and explore materials with high spin-charge conversion efficiency. Here, we demonstrate the inverse spin Hall effect in a conductive bismuth oxide. The bismuth oxide thin films with different thicknesses were prepared from a sintered bismuth oxide target by an rf-sputtering system. Then, permalloy/bismuth oxide bilayer spin pumping devices were developed, with which voltage signals corresponding to the inverse spin Hall effect were confirmed by the spin pumping technique. Furthermore, by systematical studying of bismuth-oxide thickness dependence of those spin Hall voltages, the spin Hall angle and spin diffusion length were quantitatively estimated. Our results propose a novel system with an observable inverse spin Hall effect, which expands the possibility of spintronic materials and guides a new path for the development of spin-based devices.