The electronic phase behavior and functionality of interfaces and surfaces in complex materials are strongly correlated to chemical composition profiles, stoichiometry and intermixing. Here a novel analysis scheme for resonant X-ray reflectivity maps is introduced to determine such profiles, which is element specific and non-destructive, and which exhibits atomic-layer resolution and a probing depth of hundreds of nanometers.

The structural and electronic properties of Mn x Ge 1−x alloys ͑x ഛ 0.15͒ fabricated by ion implantation are investigated by means of x-ray diffraction and synchrotron radiation photoemission spectroscopy. The diffraction patterns point to the presence of ferromagnetic Mn 5 Ge 3 nanoparticles; however, valence band spectra, interpreted by means of accurate ab initio calculations including Hubbard-like correlations, show clear fingerprints of an effective substitutional Mn dilution in the Ge semiconducting host.

X-ray diffraction, transmission electron microscopy, extended x-ray absorption fine structure spectroscopy, and x-ray photoemission spectroscopy have been used to study the structural properties of MnxGe1-x ion implanted alloys (x similar or equal to 0.04) at 240 and 270 degrees C substrate temperatures. Between 40% and 50% of the Mn atoms are found to occupy substitutional sites. No interstitial Mn atoms are found. The Mn-Ge coordination distance is 2.50(2) angstrom. Moreover, in the subsurface implanted layer [up to 32(2) nm depth] all the Mn atoms are effectively diluted in the Ge matrix, reaching a peak doping concentration of 7 +/- 1%. (c) 2006 American Institute of Physics