Thickness dependence of magnetoelastic properties and of crystallization behavior in Fe-Tb-Dy/Fe and Fe-Tb-Dy/nanocrystalline Fe-Si-B-Nb-Cu multilayers

Fe-Tb-Dy/Finemet(TM) and Fe-Tb-Dy/Fe multilayers have been prepared by ion beam sputtering on room temperature sapphire substrates (Finemet is a nanocrystalline Fe-Si-B-Nb-Cu magnetic alloy). After production, the Fe-Tb-Dy and the Finemet layers are amorphous, whereas the Fe layers are polycrystalline. Subsequent annealing leads to relaxation of the amorphous Fe-Tb-Dy layers in both cases and to crystallization of the Finemet layers for the Fe-Tb-Dy/Finemet multilayers. In this regime, the properties of the multilayers can be well described by a mixture rule of the two perfectly coupled components. In an optimum thickness range for both layers, they show very soft magnetic properties and high magnetoelasticity. Furthermore, it has been observed that crystallization of the Fe-Tb-Dy layers within the multilayer is hindered by interface stabilization as recently predicted in U. Herr, H. Geisler, H. Ippach, and K. Samwer, Phys. Rev. B 59, 13719 (1999). (C) 2000 American Institute of Physics. [S0021-8979(00)09117-9].