Effect of Ge-doping at the non-magnetic site (Si-site) of the Mn-based binary alloy Mn5Si3 has been explored through temperature-dependent x-ray diffraction, dc-magnetic, and electrical transport measurements. All the doped alloys show D88 type hexagonal structure with space group P63/mcm at room temperature and undergoes two structural distortions, hexagonal (P63/mcm) → orthorhombic (Ccmm) → orthorhombic (Cc2m), on cooling. The magnetic characters of these orthorhombic (Cc2m), orthorhombic (Ccmm), and hexagonal (P63/mcm) phases are non-collinear antiferromagnetic (AFM1), collinear antiferromagnetic (AFM2), and paramagnetic (PM), respectively. Doping of Ge results in a significant increase in the AFM1 to AFM2 transition temperature (TN1). However, the AFM2 to PM transition point remains unchanged. In addition, a reasonable increase in the critical field values of the AFM1 to AFM2 transition via another non-collinear antiferromagnetic phase (AFM1′) with increasing Ge concentration has been observed, indicating the strengthening of AFM1 and AFM1′ phases over the AFM2 phase. Such behaviors make the observation of unusual magnetic properties of undoped Mn5Si3 alloys, like inverted hysteresis loop (IHL) and thermomagnetic irreversibility (TI), more evident for these Ge-doped alloys. Further, this study unfolds the presence of conventional and inverse magnetocaloric effect and they found to decrease with Ge doping. An interesting interplay for positive and negative magnetoresistance has also been observed in all the studied alloys.

In this study, we introduce a method designed to eliminate parallax artefacts present in X-ray powder diffraction computed tomography data acquired from large samples. These parallax artefacts manifest as artificial peak shifting, broadening and splitting, leading to inaccurate physicochemical information, such as lattice parameters and crystallite sizes. Our approach integrates a 3D artificial neural network architecture with a forward projector that accounts for the experimental geometry and sample thickness. It is a self-supervised tomographic volume reconstruction approach designed to be chemistry-agnostic, eliminating the need for prior knowledge of the sample's chemical composition. We showcase the efficacy of this method through its application on both simulated and experimental X-ray powder diffraction tomography data, acquired from a phantom sample and an NMC532 cylindrical lithium-ion battery.

The high stability, high availability, and wide size-dependent bandgap energy of sulphidic semiconductor nanoparticles (NPs) render them promising for applications in optoelectronic devices and solar cells. However, the tunability of their optical properties depends on the strict control of their crystal structure and crystallisation process. Herein, we studied the structural evolution during the formation of CdS and ZnS in solution by combining in situ luminescence spectroscopy, synchrotron-based X-ray diffraction (XRD) and pair distribution function (PDF) analyses for the first time. The influence of precursor type, concentration, temperature and heating program on the product formation and on the bandgap or trap emission were investigated in detail. In summary, for CdS, single-source precursor (SSP) polyol strategies using the dichlorobis(thiourea)cadmium(II) complex and double-source precursor approaches combining Cd(CH3COO)2·2H2O and thiourea led to the straightforward product at 100 °C, while the catena((m2-acetato-O,O')-(acetate-O,O')-(m2-thiourea)-cadmium) complex was formed at 25 and 80 °C. For ZnS, the reaction between Zn(CH3COO)2·2H2O and thiourea at 100 °C led to the product formation after the crystallisation and dissolution of an unknown intermediate. At 180 °C, besides an unknown phase, the acetato-bis(thiourea)-zinc(II) complex was also detected as a reaction intermediate. The formation of such reaction intermediates, which generally remain undetected applying only ex situ characterisation approaches, reinforce the importance of in situ analysis for promoting the advance on the production of tailored semiconductor materials.

X-ray microscopy offers the opportunity to image biological and radiosensitive materials without special sample preparations, bridging optical and electron microscopy capabilities. However, the performance of such microscopes, when imaging radiosensitive samples, is not limited by their intrinsic resolution, but by the radiation damage induced on such samples. Here, we demonstrate a novel, to the best of our knowledge, radio-efficient microscope, scanning Compton X-ray microscopy (SCXM), which uses coherently and incoherently (Compton) scattered photons to minimize the deposited energy per unit of mass for a given imaging signal. We implemented SCXM, using lenses capable of efficiently focusing 60 keV X-ray photons into the sub-micrometer scale, and probe its radio-efficient capabilities. SCXM, when implemented in high-energy diffraction-limited storage rings, e.g., European Synchrotron Radiation Facility Extremely Brilliant Source and PETRA IV, will open the opportunity to explore the nanoscale of unstained, unsectioned, and undamaged radiosensitive materials.

Complementary to x-ray diffraction patterns that represent the crystal lattice in Q space, the atomic pair distribution function (PDF) describes the structure of a material as a histogram of interatomic distances r in real space.The total scattering (TS) approach that enables PDF analysis requires that scattering data is collected over a wide Q range of the order of 20 Å -1 and subsequent Fourier transformation of the entire scattering pattern into direct space.While TS at high-energy beamlines has become a standard routine for bulk-type samples, the unfavorable thickness ratio of a thin film (nanometer regime) to its substrate (micrometer regime) limits the detectability of the film signal in simple transmission geometry as described e.g. in Ref. [1].Therefore, we applied the high-energy surface diffraction technique established for single-crystal surfaces [2] to less ordered films and thus pushed the capabilities for PDF analysis of thin films to unprecedented limits in terms of minimum thickness and time resolution.[3,4] Besides polycrystalline and textured metal and oxide layers, we studied amorphous and naocrystalline thin films.By careful data treatment, we successfully derived PDFs of comparable data quality from different HfO2 films with thicknesses down to 15 nm independent on their degree of ordering with domain sizes between ~5 and >30 Å.All films were deposited on fused silica which provides an easily scalable background to subtract from the sample data to isolate the film signal.Real thin film devices e.g. for electronic applications, however, typically consist of multiple layers, and the film growth is largely affected by the nature of the underlying layer.Therefore, we further developed grazing incidence total scattering towards a depth-resolving method by scanning the incidence angle.In this way, the technique provided insight into the structure of different types of bilayer samples studied for their use e.g. in next-generation computer memory applications.PDFs were successfully extracted from the individual layers of different combinations and stackings of amorphous and crystalline materials exhibiting high and low (electron) density and, hence, x-ray scattering power from TiO2 to Pt [5].As thermal treatment is an essential part of thin film device manufacturing, we are developing a laser-interferometer based system that, beyond data collection during isothermal heat-treatment as applied in [4], enables following structural changes during variabletemperature processes up to several hundred degrees.Fig. 1 shows data from the proof-of-concept experiment on a 30 nm HfO2 thin film deposited by chemical vapor deposition in an amorphous state, crystallized in situ while continuously acquiring TS data.Figure 1.PDFs of an amorphous hafnium oxide film acquired during crystallization at the given heating rate of 100 K min -1 , incl. the fluctuations of the sample and the actual motor movements necessary to compensate for the thermal expansion.

The rhombohedral distortion-driven occurrence of the spontaneous electric polarization at a reasonably high temperature $(T)$ and an exchange bias (EB) effect below the antiferromagnetic (AFM) N\'eel temperature $({T}_{N})$ are revealed in ${\mathrm{ZnFe}}_{2}{\mathrm{O}}_{4}$. We observe the magnetic memory effect, suggesting a cooperative glassy magnetic state below ${T}_{N}$. The phase separation between the long-range AFM and the glassy magnetic component leads to the EB effect below ${T}_{N}$. The synchrotron diffraction studies confirm a structural transition to a polar $R3m$ structure from the cubic spinel structure, involving a strong rhombohedral distortion. This distortion correlates with the occurrence of the spontaneous electric polarization $(P)$ below $\ensuremath{\sim}110$ K $({T}_{\text{FE}1})$, which is accompanied by a short-range order (SRO). The $P$-value enhances further due to an additional rhombohedral distortion below ${T}_{N}$. A considerable magnetoelectric (ME) coupling is detected below ${T}_{\text{FE}1}$. The increase of $P$ is $\ensuremath{\sim}7.2$% for 5 T at the liquid nitrogen temperature. There has been a fundamental interest among the community in the unique result of the occurrence of ferroelectric (FE) order coexisting with SRO and having a significant ME coupling, which is accompanied by a strong rhombohedral structural distortion analogous to that observed in ${\mathrm{BiFeO}}_{3}$.

Pt(Cu0.67Sn0.33) has recently been found in a natural sample. In order to be able to characterize this new ternary compound, we synthesized it from the elements. Samples were characterized by X-ray powder diffraction, differential scanning calorimetry, thermal relaxation calorimetry, and scanning electron microscopy studies. Density functional theory-based model calculations complemented the experimental studies. Pt(Cu0.67Sn0.33) was already formed at a relatively low temperature of 773 K. Rietveld refinement of Pt(Cu0.67Sn0.33) has been carried out in CuAu-type or L10-type structure, space group P4∕mmm, with Pt on 0,0,0 and disordered Cu and Sn on 12, 12, 12 and Z = 1. The lattice parameters are a = 2.823(1) Å, c = 3.64(1) Å, and V = 29.00(4) Å 3; which are in good agreement with values obtained earlier on the natural sample and with the results of DFT calculations. The vibrational entropy for Pt(Cu0.67Sn0.33) is S298.15vib = 79.9(7) J mol−1 K−1. The pressure dependence up to 36(2) GPa of the unit-cell volume and the lattice parameters and unit-cell volume have been obtained by synchrotron based powder diffraction using a diamond anvil cell. A fit of a 3rd-order Birch–Murnaghan equation of state to the Pt(Cu0.67Sn0.33) (p,V)-data results in a bulk modulus of B0 = 215(27) GPa and B′ = 5(2).

A new single-phase noble metal high entropy alloy, Pt2AuCuNiSn, has been obtained at comparatively low temperatures by a solid-state reaction. A Rietveld refinement gave a satisfactory description of the X-ray diffraction data, showing that the compound crystallizes with space group Fm (3) over barm, where only one Wyckoff site is occupied. In bulk samples, SEM/EDX measurements gave no indication for chemical inhomogeneities on a pm length scale. Temperature dependent in situ diffraction measurements using high energy (lambda = 0.1204 angstrom) radiation up to 875 K show several transient phases upon heating a mixture of the elements, consistent with results of DSC measurements. The parameter describing the variability of the radii of the constituent atoms, delta r, is uncommonly large (delta r = 8.7%) and maybe the origin of the instability of this alloy a high temperatures.

High energy surface x-ray diffraction (HESXRD), x-ray reflectivity (XRR), mass spectrometry (MS) and surface optical reflectance (SOR) have been combined to simultaneously obtain sub-second information on the surface structure and morphology from a Pd(100) model catalyst during in situ oxidation at elevated temperatures and pressures resulting in Pd bulk oxide formation. The results show a strong correlation between the HESXRD and SOR signal intensities during the experiment, enabling phase determination and a time-resolved thickness estimation of the oxide by HESXRD, complemented by XRR measurements. The experiments show a remarkable sensitivity of the SOR to changes in the surface phase and morphology, in particular to the initial stages of oxidation/reduction. The data imply that SOR can detect the formation of an ultrathin PdO surface oxide layer of only 2-3 angstrom thickness.

Sputter deposition is a versatile and industrially important deposition technique for thin films, with increasing demand for matching the characteristics of thin film materials to specific requirements. The actual film properties are largely determined by sputtering parameters such as pressure conditions, temperature and power settings. By means of various X-ray diffraction and scattering techniques, it is shown that the characterization of film formation and growth is feasible in real time at synchrotron sources, thus adding an important dimension to the fundamental understanding of the evolution of thin film microstructure. In particular, grazing incidence small-angle X-ray scattering, grazing incidence X-ray powder diffraction and X-ray reflectometry are used in a complementary manner to study the influence of deposition temperature and substrate choice on the crystallization kinetics and growth of polycrystalline BaTiO$$_3$$ films.

A new tomographic reconstruction algorithm is presented, termed direct least-squares reconstruction (DLSR), which solves the well known parallax problem in X-ray-scattering-based experiments. The parallax artefact arises from relatively large samples where X-rays, scattered from a scattering angle 2θ, arrive at multiple detector elements. This phenomenon leads to loss of physico-chemical information associated with diffraction peak shape and position ( i.e. altering the calculated crystallite size and lattice parameter values, respectively) and is currently the major barrier to investigating samples and devices at the centimetre level (scale-up problem). The accuracy of the DLSR algorithm has been tested against simulated and experimental X-ray diffraction computed tomography data using the TOPAS software.

We report a ferroelectric order at ~ 98 K for NiFe2O4, which carries an inverse spinel structure with a centrosymmetric Fd3m structure at room temperature. The value of spontaneous electric polarization is considerably high as ~ 0.29 {\mu}C/cm2 for 5 kV/cm poling field. The electric polarization decreases considerably (~ 17 %) around liquid nitrogen temperature upon application of 50 kOe field, proposing a significant magnetoelectric coupling. The synchrotron diffraction studies confirm a structural transition at ~ 98 K to a noncentrosymmetric structure of P4122 space group. The occurrence of polar order is associated with an ordered occupancy of Ni and Fe atoms at the octahedral sites of the P4122 structure, instead of random occupancies at the octahedral site of the inverse spinel structure. The results propose that NiFe2O4 is a new type-II multiferroic material.

Pair distribution function (PDF) analysis has become a widely used and most effective tool to study the local structure of materials that exhibit some degree of disorder. With the increasing availability of highenergy x-ray sources equipped with large and fast area detectors, PDF has advanced into the field of in situ and operando studies. Nowadays, PDF is indispensable to follow processes in manifold bulk-type systems such as chemical reactors, electrochemical cells, mechanical testing setups, etc. More recently, the PDF technique has also been utilized to investigate thin films. Different approaches to thin film PDF have been applied, including (i) the exfoliation of the film from the substrate to grind it up into a powder [1], as well as measuring the film on the substrate in transmission under normal incidence on the surface [2]. While both of these methods are experimentally similar to bulk measurements with respect to the data collection and evaluation, they have particular drawbacks: for method (i), film-specific features such as preferred orientation may be lost and the structure modified by the mechanical treatment, and case (ii) provides an unfavorable signal to background ratio, given that the scattering from both the film and the substrate is collected and the thickness ratio is typically of the order of a factor 1000 (nanometer vs. micrometer range). In this presentation, we demonstrate the advantages of surface diffraction type PDF measurements under grazing incidence (GIPDF) to quantitatively analyze thin films with thicknesses down to a few nanometers [3]. In contrast to previous GIPDF studies, we use microfocused high energy x-rays (>60 keV) and a fast area detector to obtain high quality PDF data on the time scale of seconds to enable in situ and operando studies of thin films in real time. In a first in situ PDF analysis of thin film deposition [4], we followed the growth and strain evolution of sputtered platinum layers. This presentation highlights perspectives and challenges for future applications of GIPDF to operando and in situ thin film studies.

We report a characteristic spin-glass-like behavior in Sr3NiSb2O9, as confirmed from the low-field dc magnetometry and ac susceptibility measurements. The memory effects in the dc magnetometry exhibit similar characteristic features of the spin-glass systems. The ac susceptibility measurements provide that the frequency dependent peak-shift follows the conventional Vogel-Fulcher and dynamical scaling laws with the characteristic relaxation time to be similar to 10(-14) s. This relaxation time fits in the recommended range of similar to 10(-12) - 10(-14) s for the classical spin-glasses. Low temperature synchrotron diffraction studies point to the strong magnetoelastic coupling close to the spin-glass-like transition. The transition is found to be associated with the step-like anomalous lattice contraction. Possible origin of magnetic frustration leading to the spin-glass ground state is discussed by correlating the microstructural results, as obtained from the analysis of synchrotron diffraction studies. (C) 2018 Elsevier B.V. All rights reserved.

Data associated with syncrotron X-ray experiments conducted to show that the unit cell of bainitic ferrite is not cubic

Recent advances in storage ring technology pioneered by MAX IV (Sweden) allow synchrotron radiation sources to achieve significantly smaller emittances than those currently in operation. This new, multi-bend achromat technology can thus boost spectral brightness, enabling unprecedented experimental possibilities. The high-energy synchrotron radiation facilities ESRF (France), SPring-8 (Japan), and APS (USA) have settled upgrade plans to improve their storage ring emittance by up to two orders of magnitude at 6 GeV electron energy. PETRA III at DESY has the largest circumference with 2.3 km. As the emittance scales favorably with the storage ring size, an upgrade of PETRA III offers the unique potential to reach a diffraction limit up to X-ray energies of 10 keV. Operating at 6 GeV with an emittance of 10 pmrad, this PETRA IV facility would pave the way for new experimental opportunities, especially for those using high photon energies.