Optical constants of ferromagnetic iron via 2p resonant magnetic scattering

We have determined the optical constants at the 2p edges of iron by measuring the Bragg scattering from a Fe/V superlattice using elliptically polarized photons whose energies were tuned across the Fe 2p resonances (700-730 eV). The analysis of the Bragg peak displacement as a function of photon energy and sample magnetization, together with standard absorption measurements, allowed to determine the complete dielectric tensor for Fe, including its off-diagonal terms.