Spin wave non-reciprocity and beating in permalloy by time-resolved   magneto-optical Kerr effect
  We have studied the propagation characteristics of spin wave modes in a permalloy stripe by time-resolved magneto-optical Kerr effect techniques. We observe a beating interference pattern in the time domain under the influence of an electrical square pulse excitation at the center of the stripe. We also probe the non-reciprocal behavior of propagating spin waves with a dependence on the external magnetic field. Spatial dependence studies show that localized edge mode spin waves have a lower frequency than spin waves in the center of the stripe, due to the varying magnetization vector across the width of the stripe. 
Siddharth Rao, Jungbum Yoon, Jan Rhensius, Charanjit S. Bhatia,   Hyunsoo Yang
cond-mat.mtrl-sci cond-mat.mes-hall