Effect of surface magnetism on the x-ray spectra of hollow atoms

Overview & Synopsis

We present evidence that the detection of surface magnetism without the application of an external magnetic field is possible by studying the x-ray emission of highly charged ions interacting at grazing incidence with the sample. Measuring the 3 keV n = 2 → 1 transition in the interaction of Ar 17+ with a nickel sample at various temperatures gives access to the n = 2 ion population. The latter evolves from a half-filled to a full shell during the ferro-paramagnetic phase transition of the sample, with the ferromagnetic phase reflecting the filling blocking due to Pauli principle. This finding puts an end to a longstanding controversy arising from contradictory studies of ion-surface interaction using Auger spectroscopy.