Coherent Magnetization Rotation and Phase Control by Ultrashort Optical Pulses in [Formula presented] Thin Films

Abstract

We have applied photoexcitation by ultrashort laser pulses to single crystal thin [Formula presented] films to trigger coherent transient magnetization rotation on a subnanosecond time scale, in macroscale single domains. Moreover, by applying the photoexcitation by pairs of temporally separated pump pulses, the transient precession of the magnetization can be phase controlled, depending on the time separation between the pulses. The mechanism behind the photoexcitation originates from the modulation of the magnetocrystalline anisotropy by nonthermal hot electron spins. © 2002 The American Physical Society.