Experiments on the relation between GMR and interface roughness and on the interlayer exchange coupling across semiconductors

Abstract

Recent experiments on `giant magnetoresistance' (GMR) and interlayer exchange coupling are reviewed. For a quantitative analysis of the coupling the frequency spectrum of coupled spinwave modes as observable by means of Brillouin light scattering can be evaluated. In the microscopic mechanism leading to GMR the contribution of spin-dependent scattering originating from interface roughness of the ferromagnetic/non-ferromagnetic interfaces is unambiguously identified in the case of Fe/Cr structures. We focus furthermore on the question of coupling mediated by semiconducting interlayers, which we investigated in the case of Fe1−xSix and Si interlayers. Coupling across well ordered Si interlayers turns out to be surprisingly strong, in particular considering the fact that electrical CPP resistivity is found to be large.