Relativistic scattering calculations: On the study of surface magnetism by polarized and unpolarized electrons

A relativistic theory of elastic electron scattering, in which spin-orbit coupling and magnetic exchange interaction are both taken into account, has been applied to crystal atoms of the ferromagnets Ni, Fe and Gd. The spin-orbit- and exchange-induced scattering asymmetries obtained for polarized electrons are in good agreement with results from spin-orbit- only and exchange-only calculations. The residual deviations decrease with increasing energy. Interference effects give rise to sizeable values (up to about 4%) of a left-right scattering asymmetry for unpolarized electrons. This implies the possibility of studying surface ferromagnetism by unpolarized electron scattering.