Ion-beam induced compositional and structural changes of Al-Cu-Co multilayer stacks

• 28 single-metal nanolayers of Al, Cu, and Co were deposited on Si-substrate. • - multilayer was exposed to elevated temperatures and ion-beam mixing. • - Cu and part of Al participated in the formation of homogeneous Al 2 Cu. • - part of Co with leftover Al formed Al 9 Co 2 , rest of Co acted as stable barrier. • - systematic influence of ion-beam direction was observed on width of Al-Co sublayers. The present work deals with the investigation of ion-beam assisted annealing/mixing effects on compositional and structural changes in Al-Cu-Co multilayers. 800 nm thick Al 64 Cu 20 Co 16 multilayers prepared by magnetron sputtering deposition, consisting of 28 successive single-metal Al-, Cu-, and Co-nanolayers were treated by thermal annealing at 300 °C, 400 °C, or 500 °C as well as ion irradiation by 30 MeV Cu 5+ ions at fluences of 1x10 13 to 5x10 14 with an average flux of 2.38 × 10 10 at.cm −2 s −1 . The samples were characterized with SEM, EDX, XRD, and TEM including HAADF. In contrast to the original multilayer, the treated samples were found to consist of two types of alternating nanolayers. A wider coarse-grained structurally and chemically homogeneous single-phase nanolayer formed by Al 2 Cu, and a narrow fine-grained two-phase nanolayer, which has a heterogeneous composite structure in which the central Co sublayer (being a residue of the original single-metal Co nanolayer) is surrounded from both sides with Al-Co sublayers, consisting of Al 9 Co 2 . This Co sublayer is considered to be a diffusion blocker for Al and Cu as well as hindering the movement of borders between particular nanolayers. The formation of a ternary phase in the investigated samples was not confirmed in any of the samples.