Electron Spin Polarization Analyzers for Use with Synchrotron Radiation
Daniel T. Pierce, Robert Celotta, Michael H. Kelley, John Unguris
The measurement of the spin polarization of photoelectrons emitted from a magnetic material is discussed. An important consideration is the acceptance phase space of the spin analyzer relative to the phase space of the photoemitted electrons to be measured. Other considerations include the magnetization direction relative to the extracted beam and whether the measurements are angle integrated or angle resolved. In the logitudinal geometry where the magnetization is normal to the sample surface and along the extracted photoelecton beam, conservation of canonical angular momentum, adds an additional magnetic term to the beam emittance which is absent when the magnetization is in the same plane and transverse to the extracted beam. For angle resolved measurements in the transverse geometry, the advantages of a new, low-energy (~100 eV) spin analyzer which is easily movable, compact and efficient are discusses. Different spin analyzers are described and compared, and an analysis of their application to different spin polarized photoemission measurement configurations is given.