B18-Core EXAFS
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Diamond Proposal Number(s):
[33047]
Open Access
Abstract: Human skeletal samples burned between 200 and 1000 °C, in both aerobic and anaerobic conditions, were probed by synchrotron-based Extended X-ray Absorption Fine Structure with a view to interpret heat-induced variations in chemical composition and structure. Heat-prompted changes in Ca2+ first and second coordination shells were unveiled (regarding PO43−, CO32− and/or OH− ligands). A higher crystallinity degree was found for 800-1000 °C burning temperatures as compared to 200-700 °C, in agreement with the higher amount of organic components in moderately heated samples. The unique local structural information delivered by XAS, particularly on the Ca2+ coordination environment which determines bone's structural features and degree of crystallinity, enabled an improved understanding of the heat-elicited changes undergone by bone, not previously accessed by other techniques. This is an innovative study, with a high impact in forensic and bioarchaeological research, focused on the analysis of burned human skeletal remains.
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Oct 2026
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B21-High Throughput SAXS
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Giuseppe Junior
Mosca
,
Simone
Russo
,
Valentina
Pelliccioli
,
Martina
Quaglia
,
Pietro
Pettinari
,
Alessandro
Cangiano
,
Diego
Colombo
,
Paola
Perego
,
Giovanni L.
Beretta
,
Laura
Morelli
,
Giuseppe
Vitiello
Diamond Proposal Number(s):
[34244]
Abstract: Colloidal quantum dots (QDs) represent a versatile class of luminescent nanomaterials whose physicochemical and interfacial properties can be engineered for advanced bio-related applications. Herein, the wet-precipitation synthesis and surface engineering of ultra-small fluorine-doped ZnO quantum dots (F/ZnO QDs) were proposed and their formulation into stable amphiphilic nanosystems using synthetic glycoglycerolipids. To control aggregation and interfacial behavior, the QDs were first capped with oleylamine and subsequently functionalized through an emulsion-based approach with mono-acyl or di-acyl glycoglycerolipids, yielding double-coated amphiphilic nanoformulations. The resulting materials were extensively characterized by TEM, DLS, zeta-potential measurements, XRD, FTIR/ATR, UV–Vis, and fluorescence spectroscopy, allowing to explore correlations between surface chemistry, colloidal stability, and optical properties. Glycoglycerolipid functionalization led to a marked improvement in aqueous dispersibility and long-term colloidal stability while preserving the enhanced fluorescence induced by fluorine doping. Biological assays confirmed the cytocompatibility of the coated QDs and supported their suitability for further biointerface studies. This work highlights glycoglycerolipid-based amphiphilic coatings as an effective strategy to tailor the surface and colloidal properties of ZnO-based QDs, enabling the development of stable luminescent nanomaterials as biocompatible nanoprobes and for bio-interfacial applications.
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Aug 2026
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I15-Extreme Conditions
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Diamond Proposal Number(s):
[7758, 8615]
Open Access
Abstract: The β′-Gd2(MoO4)3 phase is one of the most well-known multiferroic materials, exhibiting both ferroelectricity and ferroelasticity under ambient conditions, with a complex temperature-pressure phase diagram. In this study, we review the pressure-dependent behavior of the RE2(MoO4)3 compound family (where RE ≡ Pr–Ho), which crystallizes in the β′-phase, with the β-phase being the paraelectric parent structure. Eu, Tb, and Ho molybdates were synthesized via solid-state reactions, ensuring the absence of impurities. High-pressure experiments at DIAMOND synchrotron revealed that the β′-phase persists at low-pressures. At approximately 2 GPa, new peaks emerged, which were refined as a mixture of the β′-phase, other rare-earth molybdates, and oxides, some of which have been detected in earlier stages of synthesis. The β′-phase became distorted with increasing pressure while coexisting with these new phases, whose average unit cell volume was found to lie between that of the β′-phase and the formed distorted phase. Ultimately, this multiphase crystalline decomposition acts as a precursor to pressure-induced amorphization, leading to a loss of long-range periodicity without complete loss of local order. The onsets of pressure-induced decomposition, distortion of the β′-phase and apparent amorphization increase as the ionic radius of the rare-earth element decreases. This scenario of irreversible structural disorder accumulated through phase coexistence is consistent with previous studies and resolves a debate persisting for over half a century.
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Aug 2026
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B07-B1-Versatile Soft X-ray beamline: High Throughput ES1
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Diamond Proposal Number(s):
[43895]
Open Access
Abstract: X-ray photoelectron spectroscopy (XPS) is a major technique in catalyst research due to its ability to determine chemical states on the surface. Near ambient pressure XPS (NAP-XPS) enables in situ analysis, offering valuable insight into catalytic processes. However, modern catalysts are often supported on non-conductive supports such as TiO2 or SiO2, which can present significant challenges for XPS analysis due to charging and differential charging. These issues can distort spectral data, rendering data unusable and wasting valuable instrument time. While several sample preparation strategies exist, many are limited by not allowing high temperature analysis, the risk of sample loss (e.g., from powder flaking off), or continued susceptibility to charging. In this work, we introduce a simple, robust, and time-efficient method for mounting catalyst powders by compressing them between aluminium foil disks. This approach provides excellent sample hold, minimises charging effects, and is suitable for high-temperature NAP-XPS analysis and synchrotron x-ray sources. The method addresses key limitations of conventional preparation techniques and enables more reliable characterisation of insulating catalyst materials.
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Aug 2026
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B18-Core EXAFS
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Diamond Proposal Number(s):
[30629]
Abstract: Geopolymer cements are highly promising materials for long-term immobilisation of Strontium-90 radioactive waste, offering superior durability and cation binding sites compared to conventional Portland cement matrices. This study investigates the influence of prolonged leaching on the Sr immobilisation mechanism and structural integrity of metakaolin-based geopolymers using the ANSI/ANS 16.1 semi-dynamic leaching test. All geopolymers demonstrated high Sr retention, with Leachability Indices at least 14.7 for all samples, significantly exceeding the industry guideline of 6.0, confirming their effectiveness. Importantly, potassium silicate–activated geopolymers exhibited reduced Sr release and substantially lower leaching rates than sodium silicate–activated geopolymers. Multiscale spectroscopic and diffractometric analysis, including synchrotron X-ray absorption spectroscopy and multinuclear high-field solid-state MAS NMR probing 39K, 23Na, 27Al, and 29Si, revealed that the alkali aluminosilicate gel framework remained structurally stable after leaching for 28 days, with no significant alterations to Si and Al bonding environments. Sr release is primarily controlled by diffusion, and the dominant immobilisation mechanism is the formation of insoluble SrCO3. Atomic-level Sr structural analysis using XANES/EXAFS revealed an increase in the average Sr coordination number in both systems after leaching, with a more pronounced rise in potassium-based geopolymers, consistent with enhanced SrCO3 formation. Overall, these findings demonstrate that geopolymers maintain structural integrity during leaching and show for the first time that using potassium rather than sodium as an alkali activator is definitively more advantageous for maximising the long-term effectiveness of geopolymer wasteforms. This demonstrates their strong suitability as wasteforms for the safe long-term immobilisation of Sr-containing radioactive wastes.
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Jul 2026
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I19-Small Molecule Single Crystal Diffraction
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Diamond Proposal Number(s):
[40212]
Open Access
Abstract: The `photometric selection' approach as a high throughput, sample tolerant, low cost and highly automatable method of carrying out serial crystallography is presented. Crystalline samples are loaded and distributed onto a simple transparent substrate and an in-line camera identifies crystals using image recognition algorithms from the computer vision project OpenCV. In contrast to established serial techniques, which generally require that crystal samples be refined with narrow size distributions and defined habits, the sample requirements when using photometric selection are shown to be minimal. We demonstrate how broadly effective photometric selection can be by collecting high-quality datasets from three exemplar systems: a small-molecule organometallic, a small-molecule organic and a metal–organic framework system. In contrast to previously established grid-scanning techniques, data collection using photometric selection can be up to six times faster.
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Jul 2026
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I15-Extreme Conditions
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Diamond Proposal Number(s):
[37838]
Open Access
Abstract: The structural behaviour of homoleptic xenon difluoride (XeF2) complexes [M(XeF2)6][SbF6]2 (M = Cu, Zn) under varying temperature and pressure has been investigated, aiming to resolve the disordered Jahn–Teller distortions in the copper complex (CuSb). At 200 K, both CuSb and its zinc analogue (ZnSb) crystallize in a layered CdCl2-type structure with the space group R3. Upon cooling below 170 (CuSb) and 160 K (ZnSb), both systems transition to isostructural phases in P1, with CuSb assuming an ordered Jahn–Teller distortion. The transformation is driven by the shortening and optimization of the Xe⋯F intermolecular contacts, forming stronger and more directional interactions, rather than by Jahn–Teller effects alone. This is supported by the observation of similar transitions in the Jahn–Teller-inactive Zn system. High-pressure experiments up to ∼2.8 GPa at room temperature show the structural stability of the high-symmetry phases, implicating kinetic barriers to further transformation. Additionally, the synthesis and structural characterization of a novel arsenic analogue, [Zn(XeF2)6][AsF6]2 (ZnAs), reveal similar layered motifs but distinct phase behaviour. Symmetry-mode analyses relate all observed phases through distortions of a common CdCl2 aristotype.
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Jul 2026
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I12-JEEP: Joint Engineering, Environmental and Processing
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Diamond Proposal Number(s):
[36935]
Open Access
Abstract: Twinning-induced plasticity (TWIP) steels exhibit exceptional combinations of strength and ductility due to the activation of deformation twinning in the FCC austenite matrix. While the formation of deformation twins during monotonic deformation has been widely studied, the reversibility of twin-related defects during cyclic tensile loading and its influence on cyclic stability remain insufficiently understood. In this study, a high-Mn twinning-induced plasticity (TWIP) steel is investigated using in situ high-energy synchrotron X-ray diffraction during continuous cyclic tensile loading under two strain amplitudes over a wide temperature range (173–523 K). Time-resolved single-shot diffraction measurements enable quantitative tracking of stacking fault energy, twin fault probability, dislocation density and texture during deformation. The results reveal partially reversible evolution of faulted microstructures during cyclic tensile loading, indicating repeated activation of twinning and detwinning processes mediated by Shockley partial dislocations. Cyclic variations in stacking and twin fault probabilities demonstrate that twin boundary migration occurs dynamically during tensile cycling even in the absence of compressive load reversal. The degree of reversibility is strongly influenced by cyclic strain amplitude and temperature, which govern the relative contributions of dislocation slip, mechanical twinning, and limited FCC-to-HCP transformation. Enhanced twinning activity at lower temperature or higher cyclic strain leads to pronounced cyclic fluctuations in defect density and texture evolution. The present time-resolved diffraction approach provides new experimental insight into the micromechanical origins of cyclic stability in low stacking fault energy austenitic alloys and highlights the role of reversible twinning and detwinning processes in governing their deformation behaviour.
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Jun 2026
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I11-High Resolution Powder Diffraction
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Diamond Proposal Number(s):
[25166]
Abstract: Layered perovskite oxides continue to be the subject of intense research efforts due to their highly tunable crystal structures, which often arise from the competition between various lattice, spin, charge and orbital degrees of freedom. In particular, a number of recent works have focused on the mechanisms through which polar phases (those with globally broken inversion symmetry) emerge through the coupling of different structural distortions. The so-called hybrid improper mechanism, in which nonpolar structural distortions couple to break inversion symmetry, has been invoked to explain the appearance of polar structures in many different layered perovskite oxides. We use a combined experimental and computational approach to investigate the pseudo-Ruddlesden–Popper system Li2SrxCa1–xTa2O7 (0 < x < 1), which exhibits multiple competing polar phases that arise through distinct mechanisms. We untangle the complex interactions between various structural modes and find that, in contrast with previous work, the hybrid improper mechanism cannot by itself account for the observed polar phases. Our work demonstrates that there are significant differences in the mechanisms through which polar phases emerge in even nominally the same family of layered perovskites, suggesting a rich playground for further exploration and functional materials design.
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Jun 2026
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I05-ARPES
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Junhyeok
Jeong
,
Yamato
Enomoto
,
Yoshimitsu
Kohama
,
Tomotaka
Nakayama
,
Kotaro
Ando
,
Kifu
Kurokawa
,
Soonsang
Huh
,
Zhuo
Yang
,
Toshihiro
Nomura
,
Matthew D.
Watson
,
Timur K.
Kim
,
Cephise
Cacho
,
Chun
Lin
,
Makoto
Hashimoto
,
Donghui
Lu
,
Shiro
Sakai
,
Takami
Tohyama
,
Kazuyasu
Tokiwa
,
Takeshi
Kondo
Diamond Proposal Number(s):
[36822, 30646, 28930, 25416]
Open Access
Abstract: Fermi arcs observed in underdoped cuprates have sparked debate over whether they represent segments of a large Fermi surface or small Fermi pockets. This ambiguity has long hindered their classification as either the conventional Bardeen-Cooper-Schrieffer (BCS) regime or the strongly coupled Bose-Einstein condensation (BEC) crossover limit. Here, using angle-resolved photoemission spectroscopy and quantum oscillations, we demonstrate the coexistence of a small Fermi pocket and a large superconducting gap in the clean inner CuO2 layers of the four-layer cuprate Ba2Ca3Cu4O8(F,O)2. This coexistence constitutes a hallmark of the BCS-BEC crossover and has remained elusive for decades. Despite the presence of antiferromagnetic (AF) order, the superconducting gap in the small pocket is remarkably large, yielding a gap-to-Fermi energy ratio (Δpocket/εF ~ 0.6) and a critical-to-Fermi temperature ratio (Tc/TF ~ 0.13) that reach the theoretical upper bound for two-dimensional superconductivity. Unexpectedly, this BCS-BEC crossover emerges not as the carrier density decreases but as it increases, abruptly within a narrow doping range of less than 1%. These results provide a long-sought microscopic foundation for the d-wave pairing mechanism in doped AF-Mott insulators.
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Jun 2026
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