Luminophores based on doped Li2B4O7 have been studied by a variety of methods (photoluminescence, pulsed cathodoluminescence and kinetics thereof, thermoluminescence, and electron paramagnetic resonance). Different impurities exhibit both interplay and competition. The interplay of impurities is expressed in the luminescence sensitization due to effective excitation energy transfer which occurs in composite impurity centers. Such centers consist of two differently incorporated impurities, one at a cationic site, another imbedded in the anionic structure. The impurities can compete for a particular position in the crystal lattice, and the priority of doping affects the result. The luminescence and thermoluminescence properties observed in the samples are connected with the structure of impurity centers. It is shown that the loss of trapped charge carriers due to instant recombination on the luminescence centers and low-temperature thermoluminescence (below 400 K) diminishes the luminescence yield for the high-temperature (above 400 K) thermoluminescence peak used in dosimetry.

X-ray and magnetometry methods are used to show that, during magnetron sputtering of Dy/Co periodic multilayer systems, the DyCo2 and DyCo3 intermetallics form. The main reason for the phase formation of various intermetallics is the structural state of buffer layer, namely, its crystalline and amorphous state in the case of crystalline and glass substrate, respectively.

Recent research has demonstrated the high potential of grazing-emission X-ray fluorescence as a nanometrology tool for structures with complex 3D architecture. The technique now allows separate reconstruction of the spatial atomic distributions of different chemical elements both vertically and laterally, which opens up new and interesting applications in the nanofabrication industry. This study compares grazing-emission fluorescence with the well established grazing-incidence X-ray fluorescence method. The comparison uses a simple 1D thin-film structure. Reconstruction of the structure by both methods is performed and the statistical uncertainties of these reconstructions are compared by means of Monte Carlo Markov-chain simulations. For the forward model a semi-analytic approach is derived which allows simulation of the fluorescence intensity. This approach takes into account both grazing-incidence and grazing-emission cases. It also accounts for an even more complex physical phenomenon, the anomalous Kossel effect. Finally, using this semi-analytic approach, an experimental scheme combining grazing-incidence and grazing-emission X-ray fluorescence is studied theoretically.

N. O. Antropov, 2 E. A. Kravtsov, M. V. Makarova, V. V. Proglyado, T. Keller, 4 I. A. Subbotin, E. M. Pashaev, G. V. Prutskov, A. L. Vasiliev, Yu. M. Chesnokov, N. G. Bebenin, V. V. Ustinov, B. Keimer, and Yu. N. Khaydukov 4, 6 Institute of Metal Physics, 620180 Ekaterinburg, Russia Ural Federal University, 620002 Ekaterinburg, Russia Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany Max Planck Society Outstation at the Heinz Maier-Leibnitz Zentrum (MLZ), D-85748 Garching, Germany National Research Center ”Kurchatov Institute”, 123182 Moscow, Russia Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow 119991, Russia (Dated: February 2, 2021)

In this study, we employed several experimental techniques to investigate structure and magnetic properties of poly( p -xylylene)–MnSb composites synthesized by low-temperature vapor deposition polymerization technique and MnSb films deposited at various temperatures. The presence of MnSb nanocrystallites in the studied films was verified by the results of X-ray diffraction, electron microscopy and Raman spectroscopy studies. The obtained data revealed the formation of Sb-rich sublayer with well-oriented Sb grains near the susbtrate, which seems to act as a buffer for the consequent poly( p -xylylene)–MnSb or MnSb layer growth. Increasing the polymer content results in qualitative change of surface morphology of studied films. At high polymer content the hybrid nanocomposite with MnSb nanoparticles embedded into poly( p -xylylene) matrix is formed. All investigated samples demonstrated detectable ferromagnetic response at room temperature, while the parameters of this response revealed a complex correlation with nominal composition, presented crystal phases and surface morphology of studied films. Estimated values of the Curie temperature of the samples are close to that of bulk MnSb.

The structure of a material promising for magnetic memory elements based on Fe/Pd/Gd/Pd superlattices has been investigated by X-ray analysis and electron microscopy. Microstructural transformations in the superlattices and the influence of microstructure modification on the magnetic properties of the system are determined. It is shown that intense diffusion of Pd atoms to Gd layers occurs in the superlattices under study. The presence of a paramagnetic Pd layer changes the character of exchange interaction between neighboring ferromagnetic layers due to the induced magnetic moment on Pd atoms near the interface because of the interface imperfection. Nanocrystalline inclusions are found in the Pd/Gd/Pd layers, which are suggested to affect the specificity of magnetic ordering in these systems, as confirmed by magnetic measurements.

A theoretical formalism for quantitative description of X-ray diffraction from Langmuir monolayers under conditions of total external reflection has been developed. The proposed approach, based on the distorted-wave approximation, allows to consider physical mechanisms for plotting diffraction curves and maps (in the reciprocal space) for real monolayers and describe self-consistently specific features of Bragg peaks. The resulting algorithm can easily be implemented on a personal computer, which provides the opportunities to carry out numerical simulation of experimental two-dimensional diffraction intensity maps and determine reliably both the mean values of structural parameters of layers and their rms deviations.

The development of new approaches to structural diagnostics of bioorganic molecular films is indispensable key to success in advanced nanotechnologies. Surface-sensitive X-ray techniques, such as grazing incidence diffraction (GIXD), provide the fullest insight into the structural parameters of nanosized materials and processes that flow within them. Highly intensive X-ray sources – synchrotrons, offered a real opportunity to implement GIXD measurements on weakly scattering systems and brought the diagnostics of bioorganic films to a fundamentally new level. Commonly used methods for calculation GIXD data of Langmuir films are qualitative in nature or based on the powder diffraction approximations [1] which do not take into account specific interaction between ordered molecules and radiation under total external reflection conditions. The elaborated theoretical approach takes into consideration strongly limited penetration depth, random orientation of Langmuir film clusters, distribution of the monolayer parameters in the film and instrumental function. For quantitative analysis of GIXD scattering maps new software has been developed based on this approach which allows to fitting 2D experimental maps and provides detailed information about radiation damage and real structure of 2D molecular nanosystems. The crucial point

Complex studies of magnetic periodic metallic systems based on Dy/Gd layers have been carried out by X-ray diffraction, resonance X-ray reflectometry, transmission electronic microscopy, and energydispersve microanalysis. The application of these methods and joint analysis of their results provide an effective approach to study of the structure and determination of the parameters of individual layers and interfaces and their structural quality with a high degree of reliability.

Thin films of MnxSi1-x alloys with different Mn concentration x approximate to 0.44-0.63 grown by the pulsed-laser deposition (PLD) method onto the Al2O3 (0001) substrate were investigated in the temperature range 4-300K using ferromagnetic resonance (FMR) measurements in the wide range of frequencies (f = 7-60GHz) and magnetic fields (H = 0-30 kOe). For samples with x approximate to 0.52-0.55, FMR data show clear evidence of ferromagnetism (FM) with high Curie temperatures T-C similar to 300 K. These samples demonstrate the complex and unusual character of magnetic anisotropy described in the frame of phenomenological model as a combination of the essential second-order easy-plane anisotropy contribution and the additional fourth-order anisotropy contribution with the easy direction normal to the film plane. We explain the obtained results by a polycrystalline (mosaic) structure of the films caused by the film-substrate lattice mismatch. Copyright (C) EPLA, 2016

The effect of the chromium layer thickness on the magnetic state of an [Fe/Cr/Gd/Cr] n multilayer structure is studied. A series of Fe/Cr/Gd structures with Cr spacer thicknesses of 4–30 Å is studied by SQUID magnetometry and ferromagnetic resonance in the temperature range 4.2–300 K. The obtained experimental results are described in terms of an effective field model, which takes into account a biquadratic contribution to the interlayer coupling energy and a nonuniform magnetization distribution inside the gadolinium layer (which was detected earlier). Depending on the magnetic field and temperature, the following types of magnetic ordering are identified at various chromium layer thicknesses: ferromagnetic, antiferromagnetic, and canted ordering. A comparison of the experimental and calculated curves allowed us to determine the dependence of the bilinear (J 1) and biquadratic (J 2) exchange constants on chromium layer thickness t Cr. Weak oscillations at a period of about 18 Å are detected in the J 1(t Cr) dependence in the range 8–30 Å. The interlayer coupling oscillations in the system under study are assumed to be related to the RKKY exchange interaction mechanism via the conduction electrons of Cr.