Study of domain wall dynamics in GdFeCo using double high-speed photography

Using the technique of double high-speed photography method, we show that an external magnetic field triggers in GdFeCo domain wall motion with velocities up to 1.2 km/s. The velocity saturates increase driving field. Contrary earlier experiments on iron garnets, did not succeed detect any effect femtosecond laser pulses velocity, even if were strong enough reverse magnetization. Keywords: ferrimagnetism, dynamics, Faraday effect.