Spin dynamics in antiferromagnetic nanostructured materials from ab-initio calculations: formation and stability of skyrmions

Abstract

The rational design of new magnetic materials with potential applications in spintronics is aimed in this project. Emphasis will be given to the investigation of magnetism in nanostructured systems with complex magnetic configurations and skyrmions emergence. Antiferromagnetic and/or synthetic antiferromagnetic systems (AFS) are going to be studied, due to the promising possibility of low dissipative transportation without heat production, besides a significantly faster spins dynamics compared to ferromagnetic materials. The systems to be studied are multilayers mainly of the type Pt/Co/NM/M/Pt where NM = Cu, Ru, Ir, W and M = Fe, Co, Ni. Different atomic combinations will be explored in these materials, investigating the formation, size, stability, and manipulations of AFS skyrmions, as the layers thickness are varied. Ferromagnetic multilayers as Pd/Co/Pd will also be studied, in order to theoretically inspect the existence of skyrmions at room temperature and zero external field, as observed experimentally in literature. It is foreseen that these deep investigations and comparative analysis allow us to establish which are the contributions to the formation of small and stable skyrmions and map out the obtained results into the most challenging AFS systems. The state-of-art theoretical arsenal for in silico simulations of these systems will be applied: the DFT based RS-LMTO-ASA method, for calculation of magnetic ground state properties, and the UppASD code for Spin Dynamics calculations as a function of temperature and applied field. Theoretical and computational developments will be performed in collaborations with theoretical groups abroad and an experimental group in Brazil. The complexity and novelty of the mechanisms involved in the formation of skyrmions in AFS materials is the great challenge addressed in the present project. (AU)