摘要

In this talk, I will present a new type of spin-transfer torque. Like an electron, a magnon, the quantum of spin wave, has also spin. Thus, it is possible for magnons to transfer their spin angular momentum to a magnet, resulting in all magnonic spin-transfer torque. As an example, I will discuss the spin wave transportation through a transverse magnetic domain wall (DW) in a magnetic nanowire. A magnon carries opposite spins on the two sides of the DW. It is found that spin wave passes through a DW without reflection, and each magnon shall transfers 2 angular momentum to the DW. As a result, this magnonic spin-transfer torque can efficiently drive a DW to propagate in the opposite direction to that of the spin wave. This finding opens a door to the application of magnetic insulators in spintronic devices. The advantages of using magnetic insulators include smaller dissipation rates and low energy consumption.

报告人简介

王向荣，香港科技大学终身教授；1984年毕业于武汉大学物理系，同年通过中美联合招收物理研究生选拔考试(CUSPEA) 赴美深造；1990年在美国罗彻斯特大学(University of Rochester)获博士学位；1992受聘于香港科技大学至今。多年来致力于香港内地科研合作，是山东大学、武汉大学、北京师范大学、中科院固体物理研究所等多所学校和研究机构的客座教授，同时担任中科院物理研究所理论与计算部的顾问委员。
研究方向：在凝聚态理论领域具有丰富研究经验，研究领域包括量子霍尔效应，二维电子气量子输运，超晶格以及量子纠缠与量子计算；创造性地提出了超晶格中电流自振荡的极限环理论；从理论上揭示了磁动力学中磁畴壁运动的机理，为完全理解磁畴壁的运动规律提供了理论基础；迄今已在国际权威学术杂志发表论文过百篇，包括在《物理评论快报》(Physical Review Letters) 发表13篇。