Observation of spin helicity using nonresonant circularly polarized X-ray diffraction analysis

We have successfully detected spin chirality in prototypical multiferroic MnWO₄ wherein the helical magnetic order induces ferroelectricity using a nonresonant circularly polarized X-ray diffraction technique. The intensity of the magnetic reflection from MnWO₄ shows a clear difference between the right- and left-handed circular polarizations of the incident X-ray beam. The ratio of these intensities is in good agreement with theoretical predictions. The results clearly show that this technique is suitable for the investigation of spin chirality. Finally, we studied the spin chirality of another multiferroic material, DyMnO₃. Possible applications of this technique are also discussed.