Spin-lattice dynamics of surface vs core magnetization in Fe nanoparticles

DOS SANTOS, GONZALO; MEYER, ROBERT; APARICIO, ROMINA; TRANCHIDA, JULIEN; BRINGA, EDUARDO M.; URBASSEK, HERBERT M.

APPLIED PHYSICS LETTERS

AMER INST PHYSICS

Año: 2021 vol. 119

0003-6951

Magnetization of clusters is often simulated using atomistic spin dynamics for a fixed lattice. Coupled spin-lattice dynamics simulations ofthe magnetization of nanoparticles have, to date, neglected the change in the size of the atomic magnetic moments near surfaces. We showthat the introduction of variable magnetic moments leads to a better description of experimental data for the magnetization of small Fe nano-particles. To this end, we divide atoms into a surface-near shell and a core with bulk properties. It is demonstrated that both the magnitudeof the shell magnetic moment and the exchange interactions need to be modified to obtain a fair representation of the experimental data.This allows for a reasonable description of the average magnetic moment vs cluster size, and also the cluster magnetization vs temperature.