Coherent Magnetization Rotation and Phase Control by Ultrashort Optical Pulses in ${\mathrm{C}\mathrm{r}\mathrm{O}}_{2}$ Thin Films

Coherent Magnetization Rotation and Phase Control by Ultrashort Optical Pulses in ${C r O}_{2}$ Thin Films

Qiang Zhang, A. V. Nurmikko, A. Anguelouch, G. Xiao, and A. Gupta

Phys. Rev. Lett. 89, 177402 – Published 4 October 2002

Abstract

We have applied photoexcitation by ultrashort laser pulses to single crystal thin ${C r O}_{2}$ 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.