9月29日学术报告：Magnonics using nano-contact spin torque oscillators

发布者：系统管理员发布时间：2012-09-26浏览次数：12

题目：Magnonics using nano-contact spin torque oscillators

报告人：Prof. Johan kerman, Dept. Physics, University of Gothenburg, Sweden & Materials Physics, Royal Institute of Technology, Stockholm, Sweden

邀请人：翟亚

时间：2012年09月29日上午10:00

地点：田家炳楼203

摘要：
Nano-contact based spin torque oscillators (STOs) operate through the generation of spin waves in a region of the free layer underneath the nano-contact. The frequency and amplitude of these spin waves can be tuned by the drive current and the applied field strength and the type of spin wave mode can be controlled from propagating to localized as a function of the out-of-plane angle θe of the applied magnetic field as shown both theoretically and using micromagnetic simulations. By studying the STO signal as a function of θe, I will show that at angles θe below a certain critical angle θcr, two distinct spin wave modes can be excited: a propagating mode, and a localized mode. The experimental frequency, current threshold and frequency tuneability with current of the two modes can be described qualitatively by analytical models and quantitatively by numerical simulations. I will also show that the Oersted field strongly affects the current tuneability of the propagating mode at subcritical angles, which is also the fundamental cause of the mode hopping observed in the time-domain [5]. The nano-contact STO may very well be the ideal spin wave generator in magnonic circuits scanning micro-BLS directly demonstrates the propagation and directionality of such spin waves outside of the nano-contact region [6]. I finally suggest a number of magnonic building blocks based on spin torque driven nano-contact oscillators and the inverse spin hall effect that can act as spin wave gates, manipulators and detectors.

个人简历：
2008-present Professor in Experimental Physics, University of Gothenburg, Sweden
2005-present Senior Researcher, Royal Institute of Technology, School of ICT, Kista Sweden
2001-2005 Senior Staff Scientist, Motorola/Freescale, Tempe/Chandler, AZ, USA
1995 (summer) Visiting Scientist, Hitachi-Maxell Magneto-Optic Research Laboratory, Japan
1994 Research Assistant, Ecole Polytechnique Fédérale de Lausanne, Switzerland
113 publications, over 30 invited talks, 4 patents. 1268 citations, most cited paper cited 138 times. Author of two Book Chapters on Magnetoresistive Random Access Memory (MRAM). Reviewer for Nature Nanotechnolgoy, Nature Communication, Phys. Rev. Lett. Appl. Phys. Lett., Phys. Rev. B, J. of Appl. Phys, J. of Magn. Magn. Mat., IEEE Trans. Magnetics, and IEEE Trans. Applied Superconductivity.