Phase resolved x-ray ferromagnetic measurements in fluorescence yield

Phase resolved X-ray Ferromagnetic Resonance (XFMR) has been measured in fluorescence yield, widening the application of XFMR to opaque samples on opaque substrates. Magnetization dynamics were excited in a Co₅₀Fe₅₀(0.7)/Ni₉₀Fe₁₀(5) bilayer by means of a continuous wave microwave excitation, while X-ray Magnetic Circular Dichroism (XMCD) spectra were measured stroboscopically at different points in the precession cycle. By tuning the x-ray energy to the L3 edge of Ni or Fe, the dependence of the real and imaginary components of the magnetic susceptibility upon the strength of an externally applied static was determined. First results from measurements on a Co₅₀Fe₅₀(0.7)/Ni₉₀Fe₁₀(5)/Dy(1) sample confirm that enhanced damping results from the addition of the Dy cap.