On Wednesday, June 14th 2023, we have the pleasure to welcome in SPINTEC Pr Chih Huang Lai from National Tsing Hua University, Taiwan. He will give us a seminar at 14:00, entitled :
Spin orbit torque switching in ferromagnetic/antiferromagnetic systems
Place : CEA Building 10.05 auditorium 445 (access to CEA needs pass (*))
visioconf link (**): https://webconf.cea.fr/bernard.dieny/P6DSVQ7M
Abstract : Exchange bias, a shift in the hysteresis loop of a ferromagnet arising from interfacial exchange coupling between adjacent ferromagnetic (FM) and antiferromagnetic (AFM) layers, is an integral part of spintronic devices. Here, we show that spin–orbit torque (SOT) generated from spin current, a promising approach to switch the ferromagnetic magnetization of next-generation magnetic random-access memory, can also be used to manipulate the exchange bias. Applying current pulses to a Pt/Co/IrMn perpendicular magnetized trilayer causes concurrent switching of ferromagnetic magnetization and exchange bias. Using time-resolved magneto-optical Kerr microscopy, we further show that the FM as well as exchange bias can be either partially or completely switched by sub-nanosecond current pulses, which enables us to achieve well controlled multi-levels. Combing electrical and spectroscopic analysis, we also reveal that the spin configurations of bulk AFM can be manipulated by SOT.
Biography : Professor Chih-Huang Lai received his Ph.D degree in materials science and engineering at Stanford University in 1997. He returns to NTHU in 1998. His research mainly focuses on novel materials for memory, information storage and renewable energy, especially on MRAM, magnetic storage and thin film solar cells. He has published more than 230 papers and awarded 50 patents. Prof. Lai’s research does not only bring several significant breakthroughs on the fundamental understanding but result in substantial impacts on real applications. Therefore, he has received many prestigious awards, including Asian Union of Magnetics Societies (AUMS) Award, IEEE fellow and MRS-T fellow. In addition, due to the good collaborations with the industry, his core technology has been transferred to strengthen technical capabilities of industry. Prof. Lai is the Associate Dean of College of Semiconductor Research and was Dean of College of Engineering, NTHU.
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(**) app web Skype https://webconf.cea.fr/bernard.dieny/P6DSVQ7M?sl=1
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