Amorphous, glass, and glass-ceramic materials practically always include a significant number (more than eight) of crystalline phases, with the contents of the latter ranging from a few wt.% to several hundredths or tenths of wt.%. The study of such materials using the method of X-ray phase analysis faces difficulties, when determining the phase structure. In this work, we will develop a method for the analysis of the diffraction patterns of such materials, when diffraction patterns include X-ray lines, whose intensities are at the noise level. The identification of lines is based on the search for correlations between the experimental and test lines and the verification of the coincidence making use of statistical methods (computer statistics). The method is tested on the specimens of a-quartz, which are often used as standard ones, and applied to analyze lava-like fuel-containing materials from the destroyed Chornobyl NPP Unit 4. It is shown that the developed technique allows X-ray lines to be identified, if the contents of separate phases is not less than 0.1 wt.%. The method also significantly enhances a capability to determine the phase contents quantitatively on the basis of lines with low intensities.
A new method for identifying crystalline phases in X-ray diffraction data has been proposed, which is especially useful for the study of multiphase materials (more than eight - ten phases) with a relatively low content (less than 1 - 3 wt\%). The method is based on a statistical analysis of data and provides an unambiguous non-quantitative criterion for the presence of one or another phase in the material. It has been shown that the method works reliably in cases where a significant number of reflexes (more than several dozen) on the diffraction pattern are comparable with intensity-to-noise r…
XDecomposer: Learning Prior-Free Set Decomposition for Multiphase X-ray Diffraction
New Laboratory of Pattern Recognition (NLPR), Institute of Automation, Chinese Academy of Sciences (CASIA)（中国科学院自动化研究所新型模式识别实验室）；School of Advanced Interdisciplinary Sciences, University of Chinese Academy of Sciences（中国科学院大学先进交叉学科学院）；Guangzhou Municipal Key Laboratory of Materials Informatics, The Hong Kong University of Science and Technology (Guangzhou)（广州市材料信息学重点实验室，香港科技大学（广州））；Green Dynamics, Australia（澳大利亚绿动公司）
Multiphase magnetic systems are common in nature and are increasingly being recognized in technical applications. One characterization method which has shown great promise for determining separate and collective effects of multiphase magnetic systems is first order reversal curves (FORCs). Several examples are given of FORC patterns which provide distinguishing evidence of multiple phases. In parallel, a visualization method for understanding multiphase magnetic interaction is given, which allocates Preisach magnetic elements as an input 'Preisach hysteron distribution pattern' (PHDP) to enabl…
Hydrogen can be stored in containers or in materials. In materials it can exist in molecular or atomic forms. The atomic form can further exist as multiple phases. Molecular hydrogen can be adsorbed on the surface or can be present inside the material. In the current work, we demonstrate for the first time, a methodology to store hydrogen in nearly all conceivable forms. At the heart of this strategy is the novel concept of storage of molecular hydrogen in metal Pd nanocontainers. The existence of multiple phases of hydrogen is confirmed by x ray diffraction, Raman spectroscopy, nuclear magnet…
Nanoscale Phase Distribution Governs Exchange Bias in Multiphase Magnetic Nanoparticles
Ecole Centrale School of Engineering, Mahindra University（印度马欣德拉大学埃科尔中央工程学院）；School of Physics, Department of Condensed Matter and Materials Physics, Aristotle University of Thessaloniki（希腊塞萨洛尼基亚里士多德大学凝聚态与材料物理系物理学院）；Center for Interdisciplinary Research and Innovation, Aristotle University of Thessaloniki（希腊塞萨洛尼基亚里士多德大学跨学科研究与创新中心）；Department of Physics, Jai Prakash University（印度贾伊·普拉萨克大学物理系）；Department of Applied Physics, KTH Royal Institute of Technology（瑞典皇家理工学院应用物理系）
Reducing the positional modulation of NbO6-octahedra in SrxBa1-xNb2O6 by increasing the Barium content: A single crystal neutron diffraction study at ambient temperature for x=0.61 and x=0.34
A self-learning scientific agent for X-ray diffraction
The Hong Kong University of Science and Technology (Guangzhou)（香港科技大学（广州））；University College London（伦敦大学学院）；The Yangtze River Delta（长三角）；Institute of Automation, Chinese Academy of Sciences（中国科学院自动化研究所）
Quantitative phase analysis is one of the major applications of X-ray powder diffraction. The essential principle of quantitative phase analysis is that the diffraction intensity of a component phase in a mixture is proportional to its content. Nevertheless, the diffraction intensity of the component phases cannot be compared with each other directly since each phase has its specific diffraction power. The diffraction power of the unit cell of a crystal is well represented by the sum of the squared structure factors, which cannot be calculated directly when the structure data is unavailable. H…
Measurements of the local tetragonality in Fe-C martensite at microstructural length-scale through pattern matching of electron backscatter diffraction patterns (EBSPs) and careful calibration of detector geometry are presented. It is found that the local tetragonality varies within the complex microstructure by several per cent at largest and that the scatter in the axial ratio is increased at higher nominal carbon content. At some analysis points the local crystal structure can be regarded as lower symmetry than simple body centred tetragonal. A linear relation between the nominal carbon con…
A Hybrid Quantum Neural Network to Analyse Big Experimental Powder X-ray Diffraction Data
Finden ltd（芬登有限公司）；National Quantum Computing Centre（国家量子计算中心）；University College London（伦敦大学学院）；Research Complex at Harwell（哈威尔研究中心）；Imperial College London（帝国理工学院）
We propose a novel data-driven approach for analyzing synchrotron Laue X-ray microdiffraction scans based on machine learning algorithms. The basic architecture and major components of the method are formulated mathematically. We demonstrate it through typical examples including polycrystalline BaTiO$_3$, multiphase transforming alloys and finely twinned martensite. The computational pipeline is implemented for beamline 12.3.2 at the Advanced Light Source, Lawrence Berkeley National Lab. The conventional analytical pathway for X-ray diffraction scans is based on a slow pattern by pattern cryst…
MatDiffract: A Material-Informed Automated Analysis Platform for X-ray Powder Diffraction
Institute of High Energy Physics, Chinese Academy of Sciences（中国科学院高能物理研究所）；Spallation Neutron Source Science Center（散裂中子源科学中心）；College of Computer and Information Engineering, Henan Normal University（河南师范大学计算机与信息工程学院）；Dongguan Institute of Materials Science and Technology, Chinese Academy of Sciences（中国科学院东莞材料科学与技术研究所）；Songshan Lake Material Laboratory（松山湖材料实验室）；School of Computer Science, Sun Yat-sen University（中山大学计算机学院）
AI-Driven Structure Refinement of X-ray Diffraction
The Hong Kong University of Science and Technology (Guangzhou)（香港科技大学（广州））；Shanghai University（上海大学）；University of Science and Technology of China（中国科学技术大学）
In situ synchrotron X-ray diffraction study of flash austenitization and process design insights in medium-Manganese steels for energy applications
University of Kassel（卡塞尔大学）；Technische Universität Bergakademie Freiberg（弗莱贝格工业大学）；Karlsruhe University of Applied Sciences (HKA)（卡尔斯鲁厄应用科学大学）；Karlsruhe Institute of Technology (KIT)（卡尔斯鲁厄理工学院）
Strain and composition play a fundamental role in semiconductor physics, since they are means to tune the electronic and optical properties of a material and hence develop new devices. Today it is still a challenge to measure strain in epitaxial systems in a non-destructive manner which becomes especially important in strain-engineered devices that often are subjected to intense stress. In this work, we demonstrate a microscopic mapping of the full tensors of strain and lattice orientation by means of scanning X-ray diffraction microscopy. We develope a formalism to extract all components of s…
Incorporation of Mn in Al$_{x}$Ga$_{1-x}$N probed by x-ray absorption and emission spectroscopy, high-resolution microscopy, x-ray diffraction and first-principles calculations
采用同步辐射X射线吸收和发射光谱技术，辅以高分辨透射电子显微镜方法和密度泛函理论计算，研究了Al含量高达100%的Al $_{x}$ Ga $_{1-x}$ N：Mn样品中Mn的影响。Mn的原子和电子结构与其局域环境和价态一起建立。Al浓度高达82%的Al $_{x}$ Ga $_{1-x}$ N：Mn得到了一种没有沉淀的稀合金，并证实了Mn在外延过程中的表面活性剂作用。
Representative compounds of the new family of magnetic materials Gd5-xNdxSi4 were analyzed by X-ray diffraction at the XRD1 beamline at LNLS. To reduce X-ray absorption, thin layers of the powder samples were mounted outside the capillaries and measured in Debye-Scherrer geometry as usual. The X-ray diffraction analyses and the magnetometry results indicate that the behavior of the magnetic transition temperature as a function of Nd content may be directly related to the average of the four smallest interatomic distances between different rare earth sites of the majority phase of each compound…
Hydrogen is an efficient energy carrier that can be produced from renewable sources, enabling the transition towards CO2-free energy. Hydrogen can be stored for a long period in the solid-state, with suitable alloys. Ti-rich TiFe0.90 compound exhibits a mild activation process for the first hydrogenation, and Ti(Fe,Mn)0.90 substituted alloys can lead to the fine tuning of equilibrium pressure as a function of the final application. In this study, the crystal structure of TiFe(0.90-x)Mnx alloys (x = 0, 0.05 and 0.10) and their deuterides has been determined by in-situ neutron diffraction, while…
Tunability of the partially ordered double perovskite (PODP) and coexisting spin-glass phase in SrMn1-xWxO3 (x=0.20 to 0.40) have been studied using neutron powder diffraction (NPD), muon spin relaxation (MuSR), and magnetic susceptibility (X) measurements. Structural studies reveal that SrMn1-xWxO3 undergoes a quasi-continuous transformation from simple perovskite (Pm-3m) to PODP (P21/n) phase as x increases. Xdc(T) and Xac(T) measurements show a sharp cusp-like peak at a spin glass transition, Tg. The muon relaxation rate (λ) peaks at Tg following a critical growth, given by λ=λ(0).t-w [t=(T…
Investment in brighter sources and larger and faster detectors has accelerated the speed of data acquisition at national user facilities. The accelerated data acquisition offers many opportunities for discovery of new materials, but it also presents a daunting challenge. The rate of data acquisition far exceeds the current speed of data quality assessment, resulting in less than optimal data and data coverage, which in extreme cases forces recollection of data. Herein, we show how this challenge can be addressed through development of an approach that makes routine data assessment automatic an…
The magnetic structure and phase diagram of the layered ferromagnetic compound Fe$_3$GeTe$_2$ has been investigated by a combination of synthesis, x-ray and neutron diffraction, high resolution microscopy, and magnetization measurements. Single crystals were synthesized by self-flux reactions, and single crystal neutron diffraction finds ferromagnetic order with moments of 1.11(5)$μ_B$/Fe aligned along the $c$-axis at 4K. These flux-grown crystals have a lower Curie temperature $T_{\textrm{c}}\approx$150K compared to crystals previously grown by vapor transport ($T_{\textrm{c}}$=220K). The dif…
Analysis of XRD diffraction patterns is one of the keystones of materials science and materials research. With the advancement of data-driven methods for materials design, candidate materials can be quickly screened for the study of a desired physical property. Efficient methods to automatically analyze and identify phases present in a given pattern, are paramount for the success of this new paradigm. To aid this process, the open source python package Xray Estimation and Refinement Using Similarity (XERUS) for semi-automatic/automatic phase identification is presented. XERUS takes advantages …
The effect of substituting iron and zinc for cobalt in CaBaCo$_4$O$_7$ has been investigated using neutron diffraction and x-ray absorption spectroscopy. The orthorhombic distortion present in the parent compound CaBaCo$_4$O$_7$ decreases with increasing the content of either Fe or Zn. The samples CaBaCo$_3$ZnO$_7$ and CaBaCo$_{4-x}$Fe$_x$O$_7$ with $x \leq 1.5$ are metrically hexagonal but much better refinements in the neutron diffraction patterns are obtained using an orthorhombic unit cell. The two types of substitution have opposite effects on the structural and magnetic properties. Fe at…
Twenty-one distinct AlxCoCrFeNi alloys were rapidly prepared by laser alloying an equiatomic CoCrFeNi substrate with Al powder to create an alloy library ranging x=0.15-1.32. Variations in crystal structure, microstructure and mechanical properties were investigated using X-ray diffraction, scanning electron microscopy, scanning transmission electron microscopy and nanoindentation. With increasing Al content, the crystal structure transitioned from a disordered FCC to a mixture of disordered BCC and ordered B2 structures. While the onset of BCC/B2 formation was consistent with previously repor…
Quantitative measurements of extended defects in crystalline materials are important in understanding material behaviour. X-ray line profile analysis provides a complement to direct counting in the electron microscope, but is an indirect method and requires validation. Previous studies have focused on comparing x-ray analysis to electron microscopy results. Instead, we use simulated defective material with known defect content and apply line profile analysis to calculated diffraction profiles to directly show that line profile analysis can reliably quantify dislocations and stacking faults.
We present the results of the high-temperature neutron and x-ray diffraction experiments on the Ca3-xSrxTi2O7 (x = 0.5, 0.8, 0.85, 0.9) compounds. The ferro- to paraelectric transition in these hybrid improper ferroelectric materials arises from the so-called trilinear coupling. Depending on the Strontium content, various structures and phase transitions, different from theoretical predictions, emerge. The in-situ x-ray powder diffraction indicates a direct ferro- to paraelectric transition between the orthorhombic A21am and tetragonal undistorted I4/mmm phase for x < 0.6. We identified a redu…
Infinite-layer (IL) nickelates are an emerging class of superconductors, where the Ni$^{1+}$ valence state in a square planar NiO$_2$ coordination can only be reached via topotactic reduction of the perovskite phase. However, this topotactic soft chemistry with hydrogenous reagents is still at a stage of rapid development, and there is a number of open issues, especially considering the possibility of hydrogen incorporation. Here we study the time dependence of the topotactic transformation of LaNiO$_3$ to LaNiO$_2$ for powder samples with x-ray diffraction and gas extraction techniques. While…
