Observation of quadrupolar x-ray diffraction peaks in NdMg

In a previous paper, we discussed the use of multiaxial magnetic structures in rare-earth compounds as test systems for x-ray scattering by orbital non-collinear 4f structures. We here present an experiment using synchrotron radiation, which, meanwhile, has given encouraging results regarding this use of x-ray diffraction: the scattering of x-rays by NdMg within its multiaxial magnetic phase yields tiny Bragg reflections which are very likely to be of quadrupolar origin. Indeed, these peaks have been found at the positions and with the intensities expected for such a charge scattering.