Thickness dependence of magnetic properties of thin amorphous ferrimagnetic rare earth–transition metal multilayers

•Gd-Co/Ti multilayers were prepared by magnetron sputtering.•The temperature behaviour of magnetization depends on Gd-Co layer thickness.•Finite-size effect seems to be responsible for the Gd-Co “effective” composition change.•The electron charge transfer from Ti spacer atoms to Co atoms reduces Co spin. Gd-Co/Ti multilayers were prepared by magnetron sputtering deposition onto glass substrates. The temperature dependence of magnetization of the multilayered structures depends on the Gd-Co layer thickness. It was shown that the obtained experimental results can be satisfactorily described in the framework of the joint application of models of the “size factor” and the “molecular field”. In addition, the possible effect of the electronic structure of titanium on the average magnetic moment of Co atoms, the efficiency of which depends on the thickness of the magnetic layers was also taken into account.