MAGNETIC-FIELD-AVERAGED PHOTOEMISSION EXPERIMENTS WITH VARIABLE CHIRALITY

We report on a photoemission dichroism effect of magnetic origin which is measured between magnetic field averaged Fe 3p spectra measured wi th different chirality. By field average we mean the average of two re sults obtained with opposite directions of magnetization. Field averag ing eliminates the linear magnetic dichroism in the angular distributi on of photoelectrons, i.e., eliminates the effect of the polarization of the magnetic atoms on the photoemission angular intensity, but the alignment of magnetic moments along the magnetization axis is reflecte d in a sizeable angular photoemission line shape effect. By changing t he chirality of the experiment, i.e., the angle between the magnetizat ion axis and the reaction plane, different intensities are measured fr om the fine structure of the photoemission peak and a dichroism arises which can be qualitatively understood from atomic photoionization the ory. The effect can be exploited to study the magnetic order at antife rromagnetic surfaces as well as to study in plane anisotropy effects o n the distribution of magnetic domains in ferromagnets.