Ion beam mixing of Fe with alumina: RBS studies

We have studied ion beam mixing of Fe with alumina and Al using different masses of the ions (Ne+, Ar+), different fluences (5x1015 to 2x1017 ions/cm2) and different temperatures (RT, 423 and 573 K). Fe thin films of different thicknesses ranging from 20 to 50 nm were deposited by a thermal evaporation method. The ion energy was chosen from 30 to 110 keV such that Fd is maximum at the interface. All the specimens were analysed with RBS technique. It is found that the square of the diffusion length Dt of Fe in alumina is proportional to the ion fluence implying that mixing is due to ballistic effects (i.e., cascade mixing). Comparison of Dts shows that mixing is less in alumina than in Al. The decrease in Dt with increase in irradiation temperature for the same energy and ion fluence imply de-mixing of Fe from alumina. Annealing of the irradiated samples also show de-mixing