Dresden 2017 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 65: Poster 2

MA 65.5: Poster

Freitag, 24. März 2017, 09:30–13:00, P2-OG1

Atomistic simulation of finite temperature magnetism of nanoparticles — •András Lászlóffy, László Udvardi, and László Szunyogh — Budapest University of Technology and Economics, Budapest, Hungary

Recent experimental efforts focus on scaling down the size of spintronics and magnetic logics devices to atomic scales to maintain technological development, which requires also intensive theoretical studies. By combining the spin-cluster expansion with the relativistic local moment scheme we developed a technique to determine suitable spin models for small embedded clusters of arbitrary geometry. We calculated the spin model of uncovered and covered hexagonal Co clusters on Au(111) surface and show that the parameters strongly depend on the local environment, especially on the coordination number of the magnetic atoms. In particular, the Co clusters capped by Au atoms display strong out-of-plane magnetic anisotropy. We performed Monte Carlo simulations to calculate the temperature dependent magnetization of the systems. We found that the blocking temperature of the covered clusters with perpendicular magnetic anisotropy can be determined by calculating the variance of the magnetization in the easy direction, since its inflection point is related to the magnetic anisotropy energy of the system. The average time of the spin reversals satisfy the Néel–Arrhenius law with an energy barrier slightly higher than the magnetic anisotropy energies of the clusters.[1]

[1] A. Lászlóffy, L. Udvardi, L. Szunyogh: arXiv: 1611.09199 (2016)