Ogawa N, Seki S, Tokura Y
RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan.
1] RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan [2] PRESTO, Japan Science and Technology Agency, Tokyo 102-0075, Japan.
Sci Rep. 2015 Apr 16;5:9552. doi: 10.1038/srep09552.
Magnetic skyrmions in an insulating chiral magnet Cu2OSeO3 were studied by all-optical spin wave spectroscopy. The spins in the conical and skyrmion phases were excited by the impulsive magnetic field from the inverse-Faraday effect, and resultant spin dynamics were detected by using time-resolved magneto-optics. Clear dispersions of the helimagnon were observed, which is accompanied by a distinct transition into the skyrmion phase, by sweeping temperature and magnetic field. In addition to the collective excitations of skyrmions, i.e., rotation and breathing modes, several spin precession modes were identified, which would be specific to optical excitation. The ultrafast, nonthermal, and local excitation of the spin systems by photons would lead to the efficient manipulation of nano-magnetic structures.
利用全光自旋波光谱对绝缘手性磁体Cu2OSeO3中的磁性斯格明子进行了研究。通过逆法拉第效应产生的脉冲磁场激发锥形相和斯格明子相中的自旋，并利用时间分辨磁光检测由此产生的自旋动力学。通过扫描温度和磁场，观察到了清晰的螺旋磁子色散，同时伴随着向斯格明子相的明显转变。除了斯格明子的集体激发，即旋转和呼吸模式外，还识别出了几种自旋进动模式，这些模式可能是光激发所特有的。光子对自旋系统的超快、非热和局部激发将导致对纳米磁性结构的有效操控。
