2020 Fall Physics Colloquium 

강연일자: 2020. 10. 13. 화. 오후 5시

장소: 비대면 온라인 Zoom

강연자: 정선재 (한국 교원대)

강연주제: The dynamics of nanoscale spin structures generated 

by spin transfer torque

Spin-transfer torque (STT) driven magneto-dynamics have been received many attentions due to interesting physics as well as possible industrial applications. This STT can be utilized for the manipulation of many different nano-scale spin-dynamics such as magnetic vortice, bubble, skyrmion, droplet soliton, and spin-wave. Among these interesting dynamics, I will talk about magnetic droplet solitons observed in spin-torque nano-oscillators (STNOs) and spin-Hall effect nano-oscillators (SHNOs). 

Magnetic droplet solitons are dynamical magnetic structures which can be realized in thin magnetic film with perpendicular magnetic anisotropy (PMA) due to an attractive interaction between spin waves. The realization of this magnetic droplet soliton was proposed theoretically in 2010 in STNOs and then it was realized experimentally in 2013. Recently, many important advances in experiment have been achieved including the direct x-ray images of droplets, understanding of nucleation currents vs. applied fields, measurements of their generation and annihilation time and evidence for drift instabilities, and so on. In this talk, I will introduce my recent works as well as previous studies about magnetic droplet soliton. Magnetic droplet soliton can be utilized as current controlled microwave frequency oscillators in neuromorphic chips as nonlinear oscillators, and so I will introduce recent progress of “neuromorphic computing using spin-torque oscillators” as one example of potential applications.