Abstract: Effects of Cu underlayer on the structure of Fe₅₀Mn₅₀ films were studied. Samples with a structure of Fe₅₀Mn₅₀ (200nm)/Cu(t_Cu) were prepared by magnetron sputtering on thermally oxidized silicon substrates at room temperature. The thickness of Cu underlayer varied from 0 to 60nm in the intervals of 10nm. High-vacuum annealing treatments, at different temperatures of 200, 300 and 400℃ for 1h, respectively, on the Fe₅₀Mn₅₀(200nm)/Cu(20nm) thin films were performed. The surface morphologies and textures of the samples were measured by field emission scan electronic microscope (FE-SEM) and X-ray diffraction(XRD). Energy dispersive X-ray spectroscopy (EDX) and Auger electron spectroscopy(AES) were used to analyze the compositional distribution. It is found that Cu underlayer has an obvious induce effect on (111) orientation of Fe₅₀Mn₅₀ thin films. The induce effects of Cu on (111) orientation of Fe₅₀Mn₅₀ changed with the increase of Cu layer thickness and the best effect was obtained at the Cu layer thickness of 20nm. High-vacuum annealing treatments cause the migration of Mn atoms towards surface of the film and interface between Cu layer and substrate. With the increasing annealing temperature, migration of Mn atoms is more obvious, which leads to a Fe-riched Fe-Mn alloy film.

Key words: Fe₅₀Mn₅₀ films; Cu underlayer; migration