Swift heavy ion irradiation and annealing effects in Fe/Si multilayers

Effects of 200 MeV silver ion irradiation and thermal annealing in Fe/Si mu ltilayers with overall composition Fe50Si50 have been studied. Two multilay ers with Fe layer thickness of 19 and 62 Angstrom have been studied. While in the first case Fe layer is amorphous in structure, in the second case it has a crystalline bcc structure. X-ray reflectivity study shows that, at t his composition both thermal annealing and heavy ion irradiation result in significant interdiffusion between the Fe and Si layers. However, while the products of thermal annealing depend upon the initial structure of the Fe layer, in the case of swift heavy ion irradiation the final phases formed a re similar in the two multilayers. The results of heavy ion irradiation can be understood in terms of the thermal spike model with the conjecture that in the wake of the 200 MeV Ag ions the temperature rises to a value at whi ch the effect of the initial structure of Fe layer on the mutual diffusivit ies of Fe and Si becomes insignificant, (C) 1999 Elsevier Science B.V. All rights reserved.