Figure 3
From: Spin-orbit torques associated with ferrimagnetic order in Pt/GdFeCo/MgO layers

Schematic of ST-FMR measurement. Inserted diagram illustrates the diffusion of Gd atoms toward MgO and a possible formation of a thin GdOx layer at the top of the alloy. The FeCo is richer in the vicinity of the Pt layer whereas Gd and GdOx richer in proximity to MgO.