Magnetic circular dichroism and spin polarization in 3d⃗4f resonant photoemission from Tb metal in the perpendicular geometry

We present combined experimental and theoretical results for the magnetic circular dichroism (MCD) in resonant 4f photoemission (RPE) from Tb metal in the perpendicular geometry at different photon energies across the whole of the M_4,5 resonance. The atomic calculations, which take into account the full multiplet structure and the coherent second-order optical process, give excellent agreement with new experimental results for the resonant photoemission decay. The angular dependence of the MCD-RPE and its strong spin polarization in the M₅ region are also reported. For a single-configuration state the variations in the spectral shape are found to be stronger as a function of angle than as a function of photon energy. Due to the presence of the multiplet structure in the intermediate state 3d⁹4f⁹ the coherent second-order optical process is essential for a correct description of the RPE. While the analysis of the spectra in parallel geometry yields accurate values of the spin-orbit, Coulomb, and exchange interactions, only the angle dependent RPE provides the phase factors of the emitted photoelectron.