Magnetic properties of neodynium atoms in Nd-Fe multilayers studies by magnetic x-ray dichroism and Nd LII and Fe K edges

In this paper we present an experimental investigation of the magnetic properties of metallic multilayers (here Nd-Fe) by magnetic x-ray dichroism (MXD). The magnetic absorption cross sections have been measured, using a dispersive optics, on both the ${\mathit{L}}_{\mathrm{II}}$ edge of Nd and the K edge of Fe in several Nd-Fe multilayers (\ensuremath{\Lambda}\ensuremath{\approxeq}40\char21{}100 \AA{}), for temperatures ranging from 77 to 300 K. We will show that the intensity of the magnetic absorption can be roughly correlated to the ordered magnetic moments present either on Nd or Fe, and thus the MXD allows direct information to be obtained on the local magnetic properties on a given atom. Moreover, by performing systematic studies as a function of the modulation length \ensuremath{\Lambda}, we discuss the efficiency of such experiments to yield direct information about the magnetic properties of the interfaces themselves. MXD experiments also give the sense of the coupling (ferromagnetic in the present case) between the magnetic moments of Nd and Fe in those systems. MXD results are compared to those given by bulk magnetization measurements and M\"ossbauer experiments on $^{57}\mathrm{Fe}$.