DETERMINATION OF THE EXCHANGE COUPLING STRENGTHS FOR FE AU/FE/

We measure, as a function of interlayer thickness, the magnitude of th e bilinear exchange coupling in an Fe/Au/Fe trilayer, to investigate t he existing order of magnitude discrepancy between theory and experime nt. We use Fe whisker substrates, scanning electron microscopy polariz ation analysis, and reflection high-energy electron diffraction to mon itor the sample's magnetic and physical structure, and confocal magnet o-optical Kerr effect to determine the coupling. We determine the exch ange coupling strengths of the individual oscillating terms. The total bilinear coupling strength is -1.9 +/- 0.2 mJ/m(2), for a Au interlay er thickness of 4 monolayers, in substantial agreement with current th eory.