报告题目：Micromagnetic study on magnetization dynamics in magnetic nanostructures
报告时间：2019-12-02 10:00 (星期一)
报告地点：北洋园校区32教218室
报告人：颜明 教授(上海大学)

报告摘要:

Here I take the opportunity to review some of ourworks on domain-wall (DW) dynamics and spin waves (SWs) in magneticnanostructures that have been done in the past decade. The main approach usedin our study is micromagnetic simulations. We predict a massless DW in thincylindrical nanowires with its motion not limited by the so-called Walkerbreakdown [1]. In cylindrical nanotubes, it is found that the Walker breakdown threshold is much higher than that in flat nanowires due to a topological reason [2]. As a result, the DW velocity in tubes can even reach the SWpropagation speed to trigger the Spin-Cherenkov effect [2-3], which is analogous to the well-known Cherenkov radiation of lights and sonic boom. Furthermore, the DW motion in tubes breaks the chiral symmetry due to a curvature effect [4]. For a similar reason, SWs propagating in circularly magnetized tubes show an asymmetric spectrum [5].  I would also discuss a real SW Doppler effect that can occur in field/current-driven DW motion in cylindrical nanowires [6]and the SW canting effect caused by the Dzyaloshinskii-Moriyainteraction [7].

References：

1.  M. Yan, A. Kákay, S. Gliga, and R. Hertel, Phys. Rev. Lett., 104, 057201 (2010).

2.  M. Yan, C. Andreas, A. Kákay, F. García-Sánchez, and R. Hertel, Appl. Phys. Lett. 99, 122505 (2011).

3.  M. Yan, A. Kákay, C. Andreas, and R. Hertel, Phys. Rev. B 88, 220412(R) (2013).

4.  M. Yan, C. Andreas, A.Kákay, F. García-Sánchez, and R. Hertel, Appl.Phys. Lett. 100, 252401 (2012).

5.  J. A. Otalora, M. Yan, H.Schultheiss, R. Hertel, and Attila Kákay, Phys. Rev. Lett., 117, 227203(2016).

6.  H. Xia, J.Chen, X. Zeng, and M. Yan, Phys. Rev. B 93, 140410(R) (2016).

7.  J. Guo, X. Y. Zeng and M. Yan, Phys. Rev. B 96, 014404 (2017).  

报告人简介：

颜明，1995年获天津大学物理系学士；1998年获天津大学物理系硕士；2004年获美国明尼苏达大学物理系博士；2004-2006年于美国阿贡国家实验室数学及计算机科学部从事博士后研究；2006-2012年于德国尤利希研究中心PeterGruenberg Institute从事博士后研究；2012年任上海大学物理系“东方学者”特聘教授，从事微磁学和自旋电子学领域的研究。