Spin-dependent extended x-ray-absorption fine structure: Probing magnetic short-range order

The first evaluation of spin-dependent extended x-ray-absorption fine structure (SPEXAFS) is reported. The SPEXAFS at the Gd L edges for Gd metal and ${\mathrm{Gd}}_3$ ${\mathrm{Fe}}_5$ ${\mathrm{O}}_{12}$ are compared to the conventional EXAFS and discussed in terms of exchange scattering from magnetic neighbors. The SPEXAFS at the Gd ${\mathrm{L}}_2$ and ${\mathrm{L}}_3$ edges reflect the change of the photoelectron spin polarization. The Fourier transform of the SPEXAFS of the ${\mathrm{Gd}}_3$ ${\mathrm{Fe}}_5$ ${\mathrm{O}}_{12}$ only shows the magnetic neighborhood, whereas the nonmagnetic oxygen neighbors remain invisible. SPEXAFS spectroscopy is expected to become a powerful tool in the determination of the magnetic short-range order.