Multiscale modeling of ultrafast element-specific magnetization dynamics of ferromagnetic alloys

Article

关键词: EXCHANGE INTERACTIONS;    SPIN DYNAMICS;    FERRIMAGNET;    REVERSAL;    METALS;    FILMS;   

DOI  :  10.1103/PhysRevB.92.054412

来源: SCIE

【 摘 要 】

A hierarchical multiscale approach to model the magnetization dynamics of ferromagnetic random alloys is presented. First-principles calculations of the Heisenberg exchange integrals are linked to atomistic spin models based upon the stochastic Landau-Lifshitz-Gilbert (LLG) equation to calculate temperature-dependent parameters (e.g., effective exchange interactions, damping parameters). These parameters are subsequently used in the Landau-Lifshitz-Bloch (LLB) model for multisublattice magnets to calculate numerically and analytically the ultrafast demagnetization times. The developed multiscale method is applied here to FeNi (permalloy) as well as to copper-doped FeNi alloys. We find that after an ultrafast heat pulse the Ni sublattice demagnetizes faster than the Fe sublattice for the here-studied FeNi-based alloys.

【 授权许可】

Free