In-plane momentum conservation in Fe/Cr/Au/Fe(001) layered structures

We study the effect of an Au layer at one of the Cr/Fe interfaces in epitaxial Fe/Cr/Au/Fe(001) sandwich structures on the magnetic interlayer coupling behavior by magneto-optical Kerr effect measurements and on the growth by scanning tunneling microscopy. The main effect of the Au layer is the suppression of the long-period oscillations of the magnetic interlayer coupling, while the short-period oscillations become dominant although their amplitude is stronger attenuated than proportional to D-2?, where D is the total thickness of the nonferromagnetic spacer layers. These findings are explained with the shapes of the Fermi surfaces of the spacer materials (Au and Cr) and in-plane momentum conservation at the Cr/Au interface of the electrons that mediate the coupling. This interpretation implicates that the N-centered ellipse of the Cr Fermi surface is the origin of the long-period oscillations across Cr spacers. [S0163-1829(99)51030-8].