Magnetic circular dichroism study of ultrathin Ni films by threshold photoemission and angle resolved photoemission spectroscopy

Threshold photoemission magnetic circular dichroism (MCD) for 12 monolayer (ML) Ni thin films grown on Cu(0 0 1) was measured with a total electron yield method. The obtained MCD asymmetry using the total electron yield method reaches as much as 10% near the photoemission threshold. On the other hand, the MCD asymmetry in angle resolved photoemission spectra with the photon energy of 5.28 eV was also investigated for Cs/Ni(12 ML)/Cu(0 0 1) and was found to give a similar MCD asymmetry. The high MCD asymmetry in the total electron yield can be interpreted by the argument that the angle and energy selection is spontaneously achieved in the total electron yield near the photoemission threshold for low photon energy excitation.