Ultrafast optical observation of spin-pumping induced dynamic exchange coupling in ferromagnetic semiconductor/metal bilayer

Spin angular momentum transfer in magnetic bilayers offers the possibility of ultrafast and low-loss operation for next-generation spintronic devices. We report the field- and temperature- dependent measurements on the magnetization precessions in Co2FeAl/(Ga,Mn)As by time-resolved magneto-optical Kerr effect. Analysis of the effective Gilbert damping and phase shift indicates a clear signature of an enhanced dynamic exchange coupling between the two ferromagnetic (FM) layers due to the reinforced spin pumping at resonance. The temperature dependence of the dynamic exchange-coupling reveals a primary contribution from the ferromagnetism in (Ga,Mn)As.

Automated summary

Spin angular momentum transfer in magnetic bilayers offers the potential for ultrafast and low-loss operation in next-generation spintronic devices. In this study, field- and temperature-dependent measurements were conducted on the magnetization precessions in Co2FeAl/(Ga,Mn)As using time-resolved magneto-optical Kerr effect. The results indicate an enhanced dynamic exchange coupling between the two ferromagnetic layers due to reinforced spin pumping at resonance, as well as a primary contribution from the ferromagnetism in (Ga,Mn)As.