Multiscale modeling of ultrafast element-specific magnetization dynamics of ferromagnetic alloys
2015 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 92, no 5, 054412Article in journal (Refereed) Published
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.
Place, publisher, year, edition, pages
2015. Vol. 92, no 5, 054412
IdentifiersURN: urn:nbn:se:uu:diva-261238DOI: 10.1103/PhysRevB.92.054412ISI: 000359045800005OAI: oai:DiVA.org:uu-261238DiVA: diva2:851723
FunderSwedish Research CouncilEU, FP7, Seventh Framework Programme