Local electronic and magnetic structure of Ni below and above T-C: A spin-resolved circularly polarized resonant photoemission study

We report the measurement of the local Ni 3d spin polarization, not only below but also above the Curie temperature (T-C), using the newly developed spin-resolved circularly polarized 2p (L-3) resonant photoemission technique. The experiment identifies the presence of 3d(8) singlets at high energies and 3d(8) triplets at low energies extending all the way to the Fermi energy, both below and above T-C, showing that it is the orbital degeneracy of the 3d band and the Hund's rule splitting which is of utmost importance to understand Ni and other 3d ferromagnets.