物理学院 School of Physics, Nanjing University

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The general Boltzmann method for magnon transport in FMI/ NM structure

2017年12月25日

时间: 2017年12月26日(明天,星期二) 上午10:10
地点: 唐仲英楼A213
报告人:张健卫  教授 
        
同济大学
Information transport with the spin degree of freedom was adapted to revive electronic devices. In particular, magnon, the flow of quantized excitations of the spin system have been considered as the ideal carrier because of its excellent transport characters. Ferromagnetic insulators (FMIs) was most promising material for magnon devices to generate, process, and transport spin information over long distances. While, a precise magnon transport picture in FMIs thin film was still demanded. A novel complete picture of magnon transport in FMIs was builded with a new Boltzmann equation which combined magnon, phonon and spin-polarized electron system together. In three magnons scattering, we found the N-process scattering which due to dipole-dipole interaction, dominated the decay dynamics of magnon group. To conduct N-process scattering, a new spatial dependent magnon draft field U was introduced, which was describing collective local motion field in magnon. We also found N-process scattering is the physical origin that why coherence magnons can transfer to thermal magnons in FI relaxation process. With those effects, we proposed a new method try to modify generation, amplification and controlling of magnon transport and the conversion to other particles (phonon). A general Boltzmann equation with complete full magnon scattering is constructed for studying precise magnon transport and decay in ferromagnetic materials. Furthermore, governing full magnons scattering which engendered by temperature gradient, could extend the global decay length of magnetic information.

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