Abstract

Studies of spin-resolved electron momentum densities involve the measurement of the so-called magnetic Compton profile. This is a one-dimensional projection of the electron momentum distribution of only those electrons that contribute to the spin moment of a sample. The technique is applicable to ferri- and ferromagnetic materials. The profile is obtained via the inelastic “Compton” scattering of high energy X-rays typically using the ESRF and SPring-8 synchrotron X-ray sources.

Since electrons originating from different atomic orbitals have specific momentum densities, it is often possible to determine the origin of the magnetism present. Typically, interpretation requires the use of electronic structure calculations using molecular orbital and band structure approaches. By using both theoretical methods in combination, a considerable amount of information can be obtained from the experimental profiles. The value of this approach will be demonstrated with some examples of our recent research, including studies of the magnetic ground states in the frustrated spin-chain compound Ca3Co2O6, in non-stoichiometric NbFe2 and in the ferromagnetic superconductor UCoGe, as well as the determination of the Fermi level spin polarisation in spin-polarised materials.