Spin analysis

The movement of the electron spin of a ferromagnetic film in beam:

An electron consists of a GaAs photocathode source produces an electron beam spin polarized by optical pumping with circularly polarized light . By reversing the circular polarization is reversed polarization vector . The polarization vector is oriented perpendicular to the magnetization of the film. The electron beam strikes the surface at 45 ° to the normal of the sample. The film exhibits a remanent magnetization along an easy magnetization axis , after applying a pulse of an external field . The reflected beam is analyzed in energy through a retarding grid analyzer .

Finally , post- electrons are accelerated to 100 keV in order to measure the spin by a Mott detector .

To distinguish the spin precession angle of rotation , the directions of magnetization of the sample and the polarization of the electrons are interchanged during the measurement. In this way we obtain four polarizations corresponding output to the four possible combinations of the direction of polarization and magnetization. By reversing the polarization , only the precession angle changes sign , then the inversion of the magnetization changes sign at the time of the phase difference and the angle of rotation of polarization. Therefore, it is possible to obtain separately the contribution of each movement. This inversion of polarization and the magnetization technique also eliminates the effects of the spin-orbit interaction in the ferromagnetic .

For more informations, see movement-spin