Magnetic Behaviour of Tb/Si Nanoscale Multilayers with Small Thickness of Rare Earth Layers

We report the magnetic properties of Tb/Si multilayers obtained by rf-sputtering at the Tb layer thickness L_Tb = 3nm. Analysis of the magnetization processes indicates more complex behaviour than canonical spin-glass transition. It is more probable that these multilayers contain both Tb superparamagnetic particles and Tb--Si spin-glass alloys.