Ion beam induced atomic mixing in Fe/Al bilayered samples

Atomic mixing of Fe/Al bilayered samples induced by an energetic xenon beam has been studied by RBS-TEM and sheet resistivity measurements. Mixing is detected at 2.5 × 10¹⁵ Xe/cm² and then proceeds up to 2 × 10¹⁶ Xe/cm². A blocking effect of the mixing for larger doses is observed. Homogeneous concentration is not obtained across the sample. Instead a pronounced graded composition is reached. Several explanations of the mixing process and the subsequent blocking effect are suggested: — sharp gradients in the nuclear energy deposition profile which decrease with dose — grain growth phenomena — precipitation of crystalline xenon acting as efficient annihilation sinks for vacancies.