学　术

由电子科学与工程学院主办的“电子论坛”第145期特别邀请波兰比亚韦斯托克大学Andrzej Stupakiewicz教授，与我校师生共同探讨磁性介质体系中的超快光磁调控。具体安排如下，欢迎感兴趣的师生参加。

主　题：Ultrafast nonthermal all-optical switching of magnetization in dielectrics

主讲人：波兰比亚韦斯托克大学     Andrzej Stupakiewicz  教授

时　间：2024年5月15日（周三）14:00

地　点：清水河校区 五号科研楼 351会议室

内容简介：

The discovery of the all-optical switching of magnetization only by a femtosecond laser pulse triggered intense discussions about mechanisms responsible for laser-induced changes. One of the most intriguing examples is the least-dissipative mechanisms of coherent photo-magnetic switching with orthogonal linear polarizations laser pulses in iron-cobalt garnet dielectrics. The switching properties are vastly different, related to the crystal site hosting the excited Co-ions. As these ions are the source of the strong magnetic anisotropy in a garnet, their excitation between the crystal filed split states results in a coherent and ultrafast manipulation of spin-orbital interaction. Moreover, we demonstrate that the ultrafast laser excitation of iron-garnet causes toggle-switching with a train of identical laser pulses between two stable magnetic bit states. This new regime of nonthermal toggle switching can be observed in an exceptionally broad temperature range. Additionally, we demonstrated that with femtosecond pulses it is possible to write and rewrite magnetic bits with a frequency of up to 50 GHz. Moreover, another non-thermal mechanism of ultrafast magnetization switching was found in these garnets by resonant pumping of optical phonon modes. Our results reveal the principles to be employed in achieving cold and ultrafast magnetic recording in dielectrics far beyond today’s state of the art.

主讲人简介：

 Prof. Andrzej Stupakiewicz (education: Ph.D.’2000, DSc’2010, Prof’2021). In 2008-2009 he was a research fellow in Institut d’Electronique Fondamentale, Universite Paris-Sud (France) and in 2009 in Radboud University Nijmegen (Netherlands). He is interested in ultrafast magnetism, nanomagnetism and advanced magneto-optics, with a particular focus on ultrafast magnetic recording. The most important scientific achievement is the discovery of a new method of nonthermal ultrafast photo-magnetic recording in a dielectric, which was selected for "Achievements of Polish Science 2016". He has involved in European research projects (5FP, 6FP, 7FP, Horizon 2020) and successfully supervised three PhD students. He has a member of management committee in European consortium CA17123 COST, Ultrafast opto-magneto-electronics for non-dissipative information technology”. He has published more than 100 research papers, 3 patents and 27 invited talk at conferences. Currently, he is the TEAM leader of Faculty of Physics in University of Bialystok in Poland.

电子科学与工程学院

2024年5月14日