The structural properties of Fe/Al multilayers deposited by evaporation or radio frequency magnetron sputtering on a glass substrate were studied by X-ray diffraction and Transmission Electron Microscopy. It was found that for very small bilayer thickness (e. g., δFe=30 nm + δAl=1$/ nm) deposited with the magnetron sputtering technique, some of the metal is involved in a metastable amorphous phase, which is probably influenced at the interface by the disordered structure of the glassy substrate. On increasing the number of bilayers, the amorphous phase disappears from the X-ray patterns: the metal is mainly in a α-Fe type condition. Furthermore, in similar multilayers grown by thermal evaporation, Transmission Electron Microscopy analyses pointed out the presence of intermetallic Fe3Al. The coherency of these multilayers, measured on the (110) reflection of α-Fe (8 nm), remains essentially unchanged with the number of Fe and Al alternating layers, but features relatable to plastic deformation were also noticed. A correction for disorder effects reveals that the average crystallite size of multilayered samples is in fact larger than 10 nm.
Metastable structures of Fe-Al multilayers grown by evaporation and magnetron sputtering
DE LORENZI, Alessandra
1990-01-01
Abstract
The structural properties of Fe/Al multilayers deposited by evaporation or radio frequency magnetron sputtering on a glass substrate were studied by X-ray diffraction and Transmission Electron Microscopy. It was found that for very small bilayer thickness (e. g., δFe=30 nm + δAl=1$/ nm) deposited with the magnetron sputtering technique, some of the metal is involved in a metastable amorphous phase, which is probably influenced at the interface by the disordered structure of the glassy substrate. On increasing the number of bilayers, the amorphous phase disappears from the X-ray patterns: the metal is mainly in a α-Fe type condition. Furthermore, in similar multilayers grown by thermal evaporation, Transmission Electron Microscopy analyses pointed out the presence of intermetallic Fe3Al. The coherency of these multilayers, measured on the (110) reflection of α-Fe (8 nm), remains essentially unchanged with the number of Fe and Al alternating layers, but features relatable to plastic deformation were also noticed. A correction for disorder effects reveals that the average crystallite size of multilayered samples is in fact larger than 10 nm.
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