SPUPS - Spin Polarised Ultraviolet Photoelectron Spectroscopy and SPXPS - Spin Polarised X-ray Photoelectron Spectroscopy. These two techniques are identical to the UPS and XPS techniques, but they have a detector which can determine the spin of the electrons emitted from the sample surface. Hence their main use is in the study of magnetic samples. The spin detector is frequently a so-called Mott detector (named after the late Sir Neville Mott). This detector makes use of an effect discovered by Neville Mott whereby electrons scatter by different amounts in different directions depending on their spin.

In a magnetic material, the electrons can be divided into spin up and spin down bands. These bands have energies which are slightly shifted (or split) with respect to each other (in non-magnetic materials, there is no splitting). Hence, the polarisation of the electrons changes as a function of binding energy. This can be studied near the Fermi edge using SPUPS and for deeper core levels using SPXPS. The results can be compared with theoretically determined spin dependent calculations of the electronic structure of the material.

Hysteresis loops can be measured by detecting the polarisation of the secondary electrons as a function of the applied field. This technique is therefore complementary to MOKE. Secondary electrons in the region of twenty electron volts (eV) have a shorter mean free path than electrons of about one eV and hence the nature of the hysteresis loop as a function of depth into the sample can be studied.