OSCILLATORY EXCHANGE COUPLING IN FE/AU/FE(100)

Scanning electron microscopy with polarization analysis was used to investigate the interlayer exchange coupling in Fe/Au/Fe(100) sandwich structures. The films were epitaxially grown on single-crystal Fe(100) substrates. Electron diffraction measurements revealed that the Au spacer film grew with a surface reconstruction consistent with that observed for bulk Au crystals. The exchange coupling oscillates between primarily ferromagnetic and antiferromagnetic coupling for Au spacer layers up to 65 layers (13 nm) thick, but a significant biquadratic coupling component was also observed. The oscillatory coupling exhibited two components with periods of 2.48+/-0.05 layers (0.506+/-0.010 nm) and 8.6+/-0.3 layers (1.75+/-0.06 nm). The measured periods are in excellent agreement with those calculated from spanning vectors of the Au Fermi surface.