Structural properties of Ni/Tb multilayers

Thin multilayer films of alternating Ni and Tb layers (Ni = 5-80 Angstrom, t(Tb) = 30 Angstrom, 15 periods, top layer: 100 Angstrom Al) were sputter-deposited at room temperature and structurally characterised by XRD, AES depth profiling, TEM and XFA. Below a critical thickness of the Ni layers, t(Ni) approximate to 26 Angstrom, an inhomogeneous amorphous NiTb alloy phase was found due to the existence of intermixed interfaces between Ni layers deposited onto Tb layers. Comparatively smooth interfaces between Ni layers deposited onto Tb layers result in a compositionally modulated structure. At larger Ni thicknesses, t(Ni) greater than or equal to 26 Angstrom, a previously absent spatially separated fcc-Ni phase is observed in addition to the NiTb alloy phase. The corresponding results of magnetic investigations will be given elsewhere. (C) 2002 Elsevier Science B.V. All rights reserved.