The Simulation Of Femtosecond Laser Induced Ultrafast Magnetization Reversal Of TbCo Thin Films

All optical switching is an emerging recording technology by using femtosecond laser to realize ultrafast magnetization manipulation for super-high magnetic storage.TbCo films possess ferrimagnetic structure and large perpendicular anisotropy and thus have the potential to be used as a AOS material.This article based on matlab software and finite difference algorithm and we simulatethe temperature of electron gas and phonon after TbCo films irradiating by ultrafast pulse laser based on a two-temperature first,then we calculate and investigate the effects of the laser fluence,the material composition and free electron phonon coupling constants on time scales,we calculate and investigate the effects of the pulse laser energy fluence and the material composition on space scales at last.The research results show that the Tb-and Co-sublattices have completely different magnetic dynamic,and the magnetization of Co-sublattice always reversal first.Tb-sublattice magnetization switching time will be relatively early if we increase the laser fluence.Only TbCo films with low Tb content show magnetization reversal when the laser fluence is low,TbCo films all show magnetization reversal irrespective of the content of Tb when the laser power intensity is high.Low free electron phonon-coupling constant will led to low lase fluencewhich can induce magnetization reversal in TbCo films.Furthermore,the Tb content at the range of 0.20-0.28 hardly influences the spatial temperature distribution of TbxCo1-x films.As for the same components of TbCo film,using higher laser fluence,magnetization reverse domain of Co-sublatticeis larger.Thereversal domainsshrink monotonically with the increase of Tb content.As for the same laser fluence,the higher the Tb content in the TbCo thin film used,the smaller magnetization reverse domain of the Co sublattice and the more homogeneous magnetization in the reverse domain.