Giant x-ray absorption circular dichroism in magnetic ultrathin films of Fe/Cu(001)

Extraordinarily large circular dichroism has been observed in the near-edge x-ray absorption of the Fe 2${\mathit{p}}^{3/2}$ and 2${\mathit{p}}^{1/2}$ lines of monolayer magnetic films of Fe on Cu(001). This is the first reported observation of normal incidence dichroism in a metal overlayer. Analysis of such large variations using a simple and concise theoretical formulation suggests a saturation of the dichroism effect. This anlaytical approach also permits an approximate determination of the magnetic moment directly from experimental parameters.