Electron Spin Polarization in Inner-Shell Excitations in a Solid

Using a ferromagnetic solid as an array of spin-polarized atoms allows one to measure directly the spin dependence of electron scattering in core excitations. Strong spin polarization of the $3p\to 3d$ energy-loss electrons scattered from ferromagnetic ${\mathrm{Fe}}_{83}$ ${\mathrm{B}}_{17}$ has been observed. The large spin polarization in the autoionization emission satellite above the $\mathrm{MMM}$ Auger line is discussed.