Depth resolved structural study of heavy ion induced phase formation in Si/Fe/Si trilayer

Abstract

Intermixing in Si/Fe/Si trilayer induced by 120 MeV Au ions has been studied. X-ray fluorescence provides information about the depth distribution of Fe atoms, while Mössbauer spectroscopy and XAFS provide information about the changes in the local structure. In the as-deposited film Fe layer is amorphous in nature with a significant Si content in it. Irradiation to a fluence of 1 × 10 13 ions/cm 2 results in formation of non-magnetic intermixed layer with its hyperfine parameter close to those of Fe 0.5 Si with CsCl structure. XAFS measurements under X-ray standing wave condition provide depth resolved structural information.

Advances in Structural and Morphological Characterization of Thin Magnetic Films: A Review

“…The application of XSW techniques requires the special preparation of the samples. The layer of interest can be realized as a waveguide owing to the refraction index for X-rays less than unit, and an X-ray waveguide is realized, sandwiching a light (low electronic density) layer between two heavier (high electronic density) layers [209,210]. Higher resolution can be achieved by growing the layer of interest over a multilayer, acting as a Bragg mirror [211].…”

“…A fixed-q setup is required to scan the X-ray energy across the absorption edge of a specific element in the film, while keeping the SW field tuned to have antinodes at a specific depth in the film. This depth sensitivity allows for the probing of the structural, electronic and chemical properties of thin films at different depths [209,210] and can be useful to specifically probe thin-film interfaces with the substrate or other layers, which can significantly impact their macroscopic properties. Specifically wedge-shaped sample has been used [110] to specially probe the local structure characteristics of a Tb/Fe/Tb trilayer, as shown in Figure 12.…”

“…Coupling XAFS with XSW geometry is a way to provide depth selectivity insights about the structural and chemical properties of thin films and interfaces [109,110,209,210,[230][231][232]. By taking advantage of the interference between the incident and reflected X-rays, standing wave XAFS offers specific advantages for thin-film characterization.…”