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 with different chirality. By field average we mean the average of two results obtained with opposite directions of magnetization. Field averaging eliminates the linear magnetic dichroism in the angular distribution 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 reflected in a sizeable angular photoemission line shape effect. By changing the chirality of the experiment, i.e., the angle between the magnetization axis and the reaction plane, different intensities are measured from the fine structure of the photoemission peak and a dichroism arises which can be qualitatively understood from atomic photoionization theory. The effect can be exploited to study the magnetic order at antiferromagnetic surfaces as well as to study in plane anisotropy effects on the distribution of magnetic domains in ferromagnets.