Multiscale modeling of ultrafast element-specific magnetization dynamics of ferromagnetic alloys
Abstract
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.
- Publication:
-
Physical Review B
- Pub Date:
- August 2015
- DOI:
- 10.1103/PhysRevB.92.054412
- arXiv:
- arXiv:1504.00199
- Bibcode:
- 2015PhRvB..92e4412H
- Keywords:
-
- 75.40.Mg;
- 75.78.Jp;
- 75.10.Hk;
- 75.50.Bb;
- Numerical simulation studies;
- Classical spin models;
- Fe and its alloys;
- Condensed Matter - Materials Science
- E-Print:
- doi:10.1103/PhysRevB.92.054412