Magnetization reversal in exchange-coupled GdFe/TbFe studied by x-ray magnetic circular dichroism

This work is dedicated to the study of magnetization reversal processes in a ferromagnetically exchange coupled ferrimagnetic/ferrimagnetic bilayer system made of a soft magnetic GdFe layer and a hard TbFe layer. Regular magnetization measurements and x-ray magnetic circular dichroism (XMCD) measurements performed at the ESRF on a GdFe (100 nm)/TbFe (3 nm) bilayer at different temperatures are presented and compared. The XMCD measurements allowed us to study separately the magnetic contribution of Gd, Tb, and Fe at the system interface. Evidence of the creation of an interface domain wall and its compression and pinning are given. In addition to quasistatic measurements, the interface magnetization reversal was also studied using XMCD aftereffect measurements. Both magnetization and XMCD measurements are explained by considering the formation of lateral domains during the interface magnetization reversal.