物理學(xué)院“博約學(xué)術(shù)沙龍”系列報(bào)告第48期        (2013年第1期)

題  目：Spin transport and spin transfer torque in textured magnetic materials from first principles
報(bào)告人：袁喆 博士
University of Twente, The Netherlands
時(shí)  間：2013年1月4日(星期五)下午2:00
地  點(diǎn)：中心教學(xué)樓610 

ABSCTRACT：
A magnet can point up or down in a magnetic field. In magnetic materials, information is stored digitally by using two such "states" to represent ones and zeros. A proposal to store information in high-density "racetrack" memories has focused attention on how electric currents in a magnetic material are affected by twisting of the magnetism (so-called a "domain wall") in between regions ("domains") where the magnetism is either all "up" or all "down". In a recent work, we investigate diffusive transport through a number of domain wall profiles of the important magnetic alloy Ni80Fe20, Permalloy, taking into account simultaneously non-collinear magnetism, alloy disorder, and spin-orbit coupling fully quantum mechanically, from first principles. In addition to observing the known effects of magnetization mistracking and anisotropic magnetoresistance, we discover a new contribution to the resistance of a domain wall that comes from spin-orbit-coupling mediated spin-flip scattering in a textured diffusive ferromagnet. Our analysis of the numerical results indicates the finding is generally applicable to other magnetic materials where the effect might be significantly enhanced by using heavier element with larger values of the spin-orbit coupling. This work also has implications for understanding spin-transfer torque in magnetic domain walls.

簡(jiǎn)  歷：
袁喆, 1998-2002年本科就讀于清華大學(xué)物理系，2005年在清華大學(xué)物理系獲理學(xué)碩士學(xué)位，2008年在瑞典Chalmers理工大學(xué)獲理學(xué)博士學(xué)位，2009至今在荷蘭Twente大學(xué)從事博士后研究。主要研究興趣包括第一性原理電子結(jié)構(gòu)計(jì)算，及其在自旋相關(guān)的電子輸運(yùn)，自旋轉(zhuǎn)矩和磁化動(dòng)力學(xué)研究中的應(yīng)用，也包括固體和表面電子激發(fā)態(tài)的研究以及大規(guī)模并行計(jì)算。

聯(lián)系方式：物理學(xué)院辦公室（68913163）
網(wǎng)    址： http://physics.bit.edu.cn/

(審核：姜艷)