The exchange interaction of Fe across interlayers X, X = Cr, Au, Ag and Al has been investigated by means of M(H) curves and lightscattering from spinwaves. For these investigations Fe/X/Fe structures were grown with as good epitaxy and crystallinity as possible, which is documented by in situ RHEED investigations. For the coupling across Cr and Au we find oscillations as a function of the interlayer thickness with a long and a short period. For Al interlayers only long periods can be clearly resolved and for Ag no oscillations have been observed. Apart from the oscillations between ferro- and antiferromagnetic type coupling we find also contributions of 90-degrees type coupling which aligns the magnetic films perpendicular to each other. The temperature dependence of 90-degrees coupling has been investigated in the case of Au interlayers.