Monte Carlo simulation of Fe-Co amorphous nanoparticles magnetization

Magnetization simulations of ∼3 nm non-interacting Fe-Co ferromagnetic amorphous nanoparticles were made using Metropolis algorithm of Monte Carlo method. The results of core-shell model simulations describe the nanoparticles as a ferromagnetically ordered core and a disordered surface shell. They fairly reproduce the significant features observed in 3 nm Fe-Co-B nanoparticles experimental magnetization measurement at the same Fe-Co composition. They also provide a clear evidence of the role played by the local surface anisotropy and the surface-core exchange interaction in determining the magnetic properties of the nanoparticles.