X-ray Diffraction In Transmission Geometry Research Articles

Operando X-ray diffraction in transmission geometry « at home » from tape casted electrodes to all-solid-state battery

The ever-growing field of energy storage needs the development of fast cycling rate and high energy density batteries and substantial research efforts are required to characterize them for improved performances. Operando X-ray diffraction is the most effective and convenient laboratory technique to get a deep insight into structural and electrochemical changes during operating conditions of batteries. In this work, we presented our newly developed operando LeRiChe’S Cell v2 which has been used to study NMC electrode materials not only with liquid electrolyte but also in solid-state batteries. The high brilliance of our laboratory diffractometer combined with our newly developed operando LeRiChe’S Cell v2 allowed us to investigate electrode materials at high C rates in a very short span of time.

Operando X-Ray Diffraction in Transmission Geometry « at Home » from Tape Casted Electrodes to All-Solid-State Battery

Operando X-Ray Diffraction in Transmission Geometry « at Home » from Tape Casted Electrodes to All-Solid-State Battery

Влияние температуры продолжительного отжига на структуру и магнитные свойства нанокристаллического сплава FeSiNbCuB

A dependence of the soft magnetic properties of the Fe73.5Si13.5Nb3Cu1B9 alloy on the temperature of annealing (Tan) carried out in air for 2 hours at temperatures from 520 to 620°C was investigated. It was shown that with Tan increasing, the magnetic hysteresis loop broadens significantly and becomes more inclined, and the Curie temperature of the amorphous matrix surrounding the α-FeSi nanocrystals decreases. The atomic structure and phase composition of the alloy samples were investigated by X-ray diffraction in transmission geometry. After annealing at temperatures of up to 580°C, nanocrystals contain predominantly D03 phase (Fe3Si stoichiometry) and have average size of about 7 nm. Their relative fraction in the alloy increases as the temperature increases due to the additional diffusion of iron from the matrix into the nanocrystals. After annealing at Tan ≥ 600°C, the average size of the nanocrystals increases, and reflections of iron boride crystals appear in the diffractograms. The deterioration of the soft magnetic properties of the Fe73.5Si13.5Nb3Cu1B9 nanocrystalline alloy, when the annealing temperature rises from 520 to 580°C, is explained by a decrease in the silicon concentration in Fe-Si nanocrystals, which leads to a growth of the constant of the magnetocrystalline anisotropy.

Synchrotron radiation μ X-ray diffraction in transmission geometry for investigating the penetration depth of conservation treatments on cultural heritage stone materials.

The assessment of the penetration depth of conservation treatments applied to cultural heritage stone materials is a burning issue in conservation science. Several analytical approaches have been proposed but, at present, many of them are not fully exhaustive to define in a direct way the composition and location of the conservation products formed after inorganic mineral treatments. Here, we explored, for the first time, the analytical capability of synchrotron radiation μ X-ray diffraction in transmission geometry (SR-μTXRD) for the study of the crystal chemistry and penetration depth of the consolidating phases formed after the application of diammonium hydrogen phosphate (DAP) treatments on a porous carbonatic stone (Noto limestone). The SR-μTXRD approach provided unambiguous information on the nature of the newly formed calcium phosphates (hydroxyapatite, HAP, and octacalcium phosphate, OCP) with depth, supplying important indications of the diffusion mechanism and the reactivity of the substrate. Qualitative and semi-quantitative data were obtained at the microscale with a non-destructive protocol and an outstanding signal-to-noise ratio. The SR-μTXRD approach opens a new analytical scenario for the investigation of a wide range of cultural heritage materials, including natural and artificial stone materials, painted stratigraphies, metals, glasses and their decay products. Furthermore, it can potentially be used to characterize the penetration depth of a phase "A" (or more crystalline phases) in a matrix "B" also beyond the cultural heritage field, demonstrating the potential wide impact of the study.

Laue lens to focus an X-ray beam for radiation therapy

A Laue lens is an optical component composed of a set of crystals that produce a convergent beam exploiting X-ray diffraction in transmission geometry. Employment of a system formed by a properly designed Laue lens coupled with an X-ray unit to selectively irradiate tumours is proposed. A convergent beam leads to a depth dose profile with a pronounced peak at the focal depth, which may result in a high precision of the dose delivery. Using a custom-made Monte Carlo code and the GAMOS code, we carried out a design study to determine the geometry and the optimal features of the crystals composing the lens. As an application, a Laue lens capable of focusing a 80 keV beam 50 cm downstream of the lens has been designed. The lens is composed of an ensemble of Si crystals with curved diffracting planes. The lens produces a focal spot of 2 mm enclosing 7.64 × 106 photons for an electron charge of 1 mC impinging on the surface of the X-ray tube anode. The combination of these important figures of merit makes the proposed system suitable for irradiating both sub-cm and larger tumour masses efficiently. A dose of 2 Gy can be delivered to a small tumour in a few seconds, sparing at the same time the surrounding tissues.

Ion implantation for manufacturing bent and periodically bent crystals

Ion implantation is proposed to produce self-standing bent monocrystals. A Si sample 0.2 mm thick was bent to a radius of curvature of 10.5 m. The sample curvature was characterized by interferometric measurements; the crystalline quality of the bulk was tested by X-ray diffraction in transmission geometry through synchrotron light at ESRF (Grenoble, France). Dislocations induced by ion implantation affect only a very superficial layer of the sample, namely, the damaged region is confined in a layer 1 μm thick. Finally, an elective application of a deformed crystal through ion implantation is here proposed, i.e., the realization of a crystalline undulator to produce X-ray beams.

Induced magnetic anisotropy in Si-free nanocrystalline soft magnetic materials: A transmission x-ray diffraction study

In order to better understand the origin of field-induced anisotropy (Ku) in Si-free nanocrystalline soft magnetic alloys, the lattice spacing of the bcc-Fe phase in nanocrystalline Fe94−xNb6Bx (x = 10, 12, 14) alloys annealed under an applied magnetic field has been investigated by X-ray diffraction in transmission geometry (t-XRD) with the diffraction vector parallel and perpendicular to the field direction. The saturation magnetostriction (λs) of nanocrystalline Fe94−xNb6Bx was found to increase linearly with the volume fraction of the residual amorphous phase and is well described by taking into account the volume-weighted average of two local λs values for the bcc-Fe nanocrystallites (−5 ± 2 ppm) and the residual amorphous matrix (+8 ± 2 ppm). The lattice distortion required to produce the measured Ku values (∼100 J/m3) was estimated via the inverse magnetostrictive effect using the measured λs values and was compared to the lattice spacing estimations made by t-XRD. The lattice strain required to produce Ku under the magnetoelastic model was not observed by the t-XRD experiments and so the findings of this study suggest that the origin of magnetic field induced Ku cannot be explained through the magnetoelastic effect.

X-ray diffraction studies of the structure of nanocrystals in Fe73.5Si13.5B9Nb3Cu1 soft magnetic alloys before and after thermomechanical treatment

The structure of the Fe73.5Si13.5B9Nb3Cu1 soft magnetic alloy has been investigated using X-ray diffraction in transmission geometry. The initial alloy prepared by rapid quenching from the melt has a short-range order (∼2 nm) in the atomic arrangement, which is characteristic of the Fe-Si structure with a body-centered cubic lattice. The alloy subjected to annealing contains Fe-Si nanocrystals with sizes as large as 10–12 nm. The annealing under a tensile load leads to an extension of the nanocrystal lattice so that, after cooling, a significant residual deformation is retained. This can be judged from the relative shifts of the (hkl) peaks in the X-ray diffraction patterns measured for two orientations of the scattering vector, namely, parallel and perpendicular to the direction of the load applied. The deformation is anisotropic: within the accuracy of the experiment, no distortions in the [111] direction are observed and the distortions in the [100] direction are maximum. It is known that crystals with a composition close to Fe3Si exhibit a negative magnetostriction; i.e., their magnetization induced under a load (Villari effect) applied along the [100] direction is perpendicular to this direction along one of the easy magnetization ([010] or [001]) axes. In the alloy, the orientation of the nanocrystal axes is isotropic and the majority of the nanocrystals have a composition close to Fe3Si. The direction of magnetization of these nanocrystals is determined by the residual deformation of their lattice and lies near the plane perpendicular to the direction of the tensile load applied during heat treatment. This is responsible for the appearance of transverse magnetic anisotropy of the easy-plane type in the Fe73.5Si13.5B9Nb3Cu1 alloy.

A simple and inexpensive capillary furnace for variable-temperature X-ray diffraction

An inexpensive capillary furnace has been developed for variable-temperature X-ray diffraction in transmission geometry of air-stable liquid crystals and other materials. It offers temperature control with fluctuations of less than ±1 K in the range of interest for these samples, from room temperature to near 573 K. Phases can be accessed through heating or cooling with no significant overshooting of the target temperature. The furnace is designed to fit on a classical goniometer, and can be controlled by any standard temperature controller. The simple design of this furnace means that it is both inexpensive to build and easy to operate.

Hard X-ray studies of stress-induced phase transformations of superelastic NiTi shape memory alloys under uniaxial load

We examined the texture evolution in a superelastic Ni 50.7Ti 49.3 (numbers indicate at.%) alloy under applied uniaxial stress using high-energy synchrotron X-ray diffraction in transmission geometry. Texture information is identified from the intensity variations along Debye–Scherrer rings recorded on area detector diffraction images. The 1 1 0 A austenite plane normals are aligned in the rolling direction and 2 0 0 A is in the transverse direction. Due to the B2–B19′ lattice correspondence, the 1 1 0 A peak splits into four martensite peaks 0 2 0 M, 1 ¯ 1 1 M , 0 0 2 M and 1 1 1 M. The stress-induced martensite is strongly textured from twin variant selection in the stress field with 0 2 0 M aligned in the loading direction while the maxima corresponding to 1 ¯ 1 1 M , 0 0 2 M and 1 1 1 M are at 60°, 67° and 75° from the loading direction. (B19′ unit cell setting: a = 2.87 Å, b = 4.59 Å, c = 4.1 Å, γ = 96.2°). A comparison between the experimental and recalculated distribution densities for the polycrystalline NiTi shows a reasonable agreement. In addition, we compare our experimental results with a micromechanical model which is based on total energy minimization. In this case, we also observe an overall agreement.

Study of Elastic Behavior of Metallic Thin Films by 2D Synchrotron XRD and in situ Tensile Testing

AbstractUnderstanding the mechanical behaviour of nano-structured thin films in relation to their structure, in particular to the grain size, is of high importance for the development of technological applications. Model nanometric multilayer W/Au systems exhibiting different structures are elaborated. These films are supported by a (thin) polyimide substrate. Films mechanical response is characterized experimentally by tensile tests carried out in-situ in a X-ray diffractometer installed on a synchrotron source. X-ray diffraction in transmission geometry has been used to study the deformations of both phases as a function of applied load. This geometry has been developed in the aim of optimizing the experiment time.

Surface X-ray diffraction in transmission geometry

We performed transmission X-ray diffraction (TXD) experiments with a Si(1 1 1) sample and an image plate in air. A large number of crystal truncation rod (CTR) scatterings can be collected all at once in transmission geometry by suppressing thermal diffuse scattering from a bulk. This benefit makes us free from time-consuming measurements in surface X-ray diffraction. In addition, intensities along CTRs were obtained correctly. Further progress in TXD under an ultra-high vacuum condition is also discussed with the results obtained from a Si(1 1 1)-7 × 7 surface.

A 1000°C furnace forin situX-ray diffraction

A furnace covering the temperature range from 25 to 1000°C has been designed and constructed to studyin situsolid-state reactions and melting and crystallization processes, with X-ray diffraction in transmission geometry using a two-dimensional-detector system. The oven can work in low vacuum and under a controlled atmosphere.

Structural characterization of Langmuir–Blodgett films by X-ray diffraction in transmission geometry

In this paper, we present a method which employs X-ray diffraction in transmission geometry for structural determination of Langmuir–Blodgett (LB) films. The LB multilayers are deposited on the outer surface of a thin glass capillary and diffraction pattern was recorded using a pin-hole flat camera. The remarkable advantage of this method is that both the multilayer reflections and in-plane reflections are recorded in one diffraction pattern which provides the following information about the film: layer thickness, electron density profile normal to the layers, in-plane packing of molecules and tilt angle of molecular chains with respect to the plane. As an example, we have determined the lattice parameters and the electron density profile of a lead stearate LB film according to one diffraction pattern where 15 orders of layer reflections and three in-plane reflections were recorded.

Structural characterization of epitaxial BiSrCaCuO films on MgO substrates

We have studied the epitaxial growth of thin Bi 2Sr 2Ca 1Cu 2O 8 films on (001) oriented MgO substrates. These films were grown using the in-situ laser ablation process (700°C, 0.1 mbar oxygen), and they showed a perfect c-axis alignment normal to the substrate, characterised by narrow mosaic distributions and by channeling effects (low χ min values) along this direction. Despite the large difference between their lattice parameters (9%), the epitaxial growth of the BiSrCaCuO film on MgO substrate has been found evidence for using X-ray diffraction in transmission geometry, by the observation of three azimuthal adjustments of the a- and b-axes of the films with respect to the a-axis of the substrate (0°, 13° and 45°). The possible origins of such epitaxial relationships are presented and discussed.