Thickness Dependence of Sublattice Magnetization Network in GdFeCo Thin Films and Gd Thin Film Interface Insertion Effect

Rare-earth transition metal alloy thin films, which serve as crucial test specimens for creating ultrafast spintronics devices, have major composition and temperature dependencies of magnetization based on the ferrimagnetic model. Although the thickness dependency of magnetization characteristics is known even in thin film regions, this dependence is difficult to explain conventional models. This study systematically evaluated this thickness dependence and confirmed an inverse proportional trend with film thickness for two compositions. Based on these results, we propose a new model involving sublattice magnetization networks with volume difference. Using this model, we confirmed significantly suppresses the thickness dependence of magnetization in GdFeCo films which adjacent Gd thin films. Furthermore, we verified the validity of the model through the response of the all-optical magnetization swhitching phenomenon based on the sublattice magnetizations.