Dimensionality effects on the magnetization reversal in narrow FePt nanowires
Résumé
The magnetization reversal of 10 nm thick FePt nanowires has been studied for widths down to 30 nm. Above 500 nm, the magnetic domains grow within a dendritic structure. Below 300 nm, the reversal takes place by propagation of a single domain wall (DW), and the coercivity increases. Below 50 nm, the coercivity increase is such that a mix of nucleation and DW propagation appears. These results suggest that the reversal process is determined by the comparison of the wire dimensions with four characteristic lengths: the dendrite width, the disorder length, the mean edge roughness, and the nucleation distance.