L10-Ordered Systems and Exchange-Spring Magnets with Perpendicular Anisotropy

For the thinner upper layer, defects act as pinning sites for the domain wall motion, while, with increasing the upper layer thickness, the defects become preferential sites for the nucleation of reversed domains, in this way, favouring the reversal of magnetization. This effect is due to the appearance of exchange-coupling interactions among the grains that favour a more cooperative reversal of the magnetic moments.