Spin Dependence of the Absorption of X-rays

Spin dependence of the absorption of photons in the keV energy range has been studied using circularly polarized synchrotron radiation. It has been established, that the near-edge absorption coefficient contains a spin-dependent part, which is characteristic for the magnetic absorbing medium. The physical origin of this phenomenon is the ejection of a partially spin-polarized photoelectron from an unpolarized inner-core state by absorption of a circularly polarized photon. In the XANES region the spin-dependent absorption profile reflects the spin-polarization of the exchange-split final states. The observed spin-dependent EXAFS result from exchange scattering of the polarized outgoing photoelectron wave by the magnetized neighboring atoms.