报告人： 吴镝 教授

                        南京大学物理学院

时间：   2019年9月6日（周五）8：30

地点：    知新楼C座 1111室

邀请人： 颜世申 教授

内容简介：

The spin Hall angle, measuring the efficiency of the spin current and charge current conversion, varies with material and can even have opposite signs (positive in Pt and negative in W). Intuitively, one expects that the spin Hall current would be reduced if combining two metallic layers with opposite sign spin Hall angles. In this work, we studied the spin Hall magnetoresistance (SMR) in W/Pt/Y₃Fe₅O₁₂ (YIG) trilayers. We found that the SMR ratio, thus the spin accumulation at Pt/YIG interface, is enhanced with the additional ultrathin W layer. Our theoretical simulation based on the spin drift-diffusion model confirms the experimental results. Our findings not only demonstrate the incorrectness of the simple intuitive picture, but also provide a simple approach to enhance the spin accumulation. In the second part of this talk, we clarify the physical origin of the dc voltage generation in a bilayer of a conducting polymer film and a micrometer-thick magnetic insulator YIG film under the ferromagnetic resonance. The previous attributed mechanism, the inverse spin Hall effect (ISHE) in the polymer, is excluded. Thus, we argue that the dc voltage is governed by the Seebeck effect in the polymer, where the temperature gradient is created by the nonreciprocal magnetostatic surface spin wave propagation in YIG.

报告人介绍：

吴镝，南京大学物理学院教授。主要从事自旋电子学的研究。分别于1997年和2001年在复旦大学物理学系获学士和博士学位，研究生期间曾到香港科技大学和德国Max-Plank微结构物理研究所短期访问。之后在美国犹他大学和加州大学河滨分校从事博士后研究。自2007年到南京大学工作。已发表论文70余篇，其中Nature 1篇，PRL 7篇，Sci. Adv. 2篇，PRB和APL共30余篇。2004年获美国犹他大学“杰出博士后奖”，2008年获得教育部“新世纪优秀人才支持计划”， 2012年获自然基金优秀青年科学基金，2013年受聘为南京大学唐仲英特聘教授。

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