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Abstract

The effects of niobium underlayer on magnetic properties of Co80Sm20 thin films deposited on silicon substrates have been studied based on electron diffraction. The films were fabricated using dc magnetron sputtering technique. Transmission electron microscope (TEM) was used to study the structural properties of the films based on selected area diffraction (SAD). The TEM study shows that the diffraction rings of film becomes less well defined for the films deposited on the thicker niobium underlayers. The coercivity of the films increases with increasing niobium thickness up to 100 nm. Further increase of the niobium thickness leads to a decrease of coercivity. The decrease of coercivity value for films deposited on thicker underlayers i.e., 120 nm indicated that the grain size of the niobium underlayer is past the optimum value. Thus the increase and decreases of the coercivity of the films with increasing niobium thickness is discussed.