Static magnetic proximity effect in Pt/Ni1−xFex bilayers investigated by x-ray resonant magnetic reflectivity Klewe, Christoph Klewe Christoph Kuschel, Timo Kuschel Timo Schmalhorst, Jan-Michael Schmalhorst Jan-Michael Bertram, Florian Bertram Florian Kuschel, Olga Kuschel Olga Wollschläger, Joachim Wollschläger Joachim Strempfer, Jörg Strempfer Jörg Meinert, Markus Meinert Markus Reiss, Günter Reiss Günter We present x-ray resonant magnetic reflectivity (XRMR) as a very sensitive tool to detect proximity induced interface spin polarization in Pt/FM heterostructures. Different XRMR experiments are carried out and the results are evaluated for their dependence on the magneto-optical depth profile, the photon energy, the optical parameters, and the ferromagnetic material.We demonstrate that a detailed analysis of the reflected x-ray intensity gives insight into the spatial distribution of the spin polarization of a nonmagnetic metal across the interface to a ferromagnetic layer. The evaluation of the experimental results with simulations based on optical data from ab initio calculations provides the induced magnetic moment per Pt atom in the spin-polarized volume adjacent to the ferromagnet. For a series with different ferromagnetic materials consisting of Pt/Fe, Pt/Ni33Fe67, Pt/Ni81Fe19 (permalloy), and Pt/Ni bilayers we find the largest spin polarization in Pt/Fe and a much smaller magnetic proximity effect in Pt/Ni. Additional XRMR experiments with varying photon energy are in good agreement with the theoretical predictions for the energy dependence of the magneto-optical parameters and allow identifying the optical dispersion δ and absorption β across the Pt L3-absorption edge. 93 21 American Physical Society (APS) 2016