"Live" Surface Ferromagnetism in Fe Nanodots/Cu Multilayers on Cu(111)

M. A. Torija, A. P. Li, X. C. Guan, E. W. Plummer, J. Shen
2005 Physical Review Letters  
We investigate the crossover behavior from two-dimensional (2D) to three-dimensional in multilayers of magnetic nanodots grown by stacking 2D Fe nanodot assemblies on Cu(111) single crystal substrate with a Cu spacing layer. Using an in situ magneto-optical Kerr effect, we have observed a striking ferromagnetic to spin-glass-like phase transition with an increasing number of Fe dot layers. The topmost layer of the Fe dots survives the phase transition and remains ferromagnetic. This unusual
more » ... c. This unusual surface ferromagnetism is likely caused by a surface-state-mediated coupling which is stronger than the coupling in bulk layers. This is confirmed by the fact that the critical temperature of the surface ferromagnetism is considerably higher than that of the bulk spin-glass phase in the system.
doi:10.1103/physrevlett.95.257203 pmid:16384502 fatcat:f43qnoyjnrfkjjuixakcx22xuy