报告题目：Micromagnetic study on magnetization dynamics in magnetic nanostructures

报告人：颜明 教授 (上海大学)

报告时间：2019 年 12 月 2 日（周一）10：00 ~ 11：00

报告地点：北洋园校区 32 教 218 室

报告摘要

Here I take the opportunity to review some our works on domain-wall (DW) dynamics and spin waves (SWs) in magnetic nanostructures that have been done in the past decade. The main approach used in our study is micromagnetic simulations. We predict a massless DW in thin cylindrical nanowires with its motion not limited by the so-called Walker breakdown [1]. In cylindrical nanotubes, it is found that the Walker breakdown threshold is much higher than that in flat nanowries due to a topological reason [2]. As a result, the DW velocity in tubes can even reach the SW propagation 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-Moriya interaction [7].

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Peter Gruenberg 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。

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).