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Volcanic and magmatic outgassing mechanisms can determine eruptive behavior of shallow silicic magma bodies. Most outgassing mechanisms proposed take place along conduit margins, where the highest strain rates drive ascending magma to brittle failure. However, these mechanisms do not account for outgassing large volumes of magma away from the conduit walls. Here, we present a continuum of porosity preserved in the microcrystalline rhyolitic Sandfell laccolith, Eastern Iceland. Three stages in the continuum are described: porous flow bands, pore channels, and fracture bands. These deformation features are present throughout the entire exposed volume of the Sandfell laccolith in meter-long band geometries, ranging from mm- to dm-scale thickness, and interlayered with coherent, undeformed rhyolite. Using microstructural analytical methods and drawing on the result of previous experimental studies, we show that emplacement-related deformation induced strain partitioning around a crystal content of 45 % that resulted in the segregation of melt-rich and melt-poorer flow bands. Subsequent deformation induced by continued magma emplacement caused strain partitioning in the melt-rich flow bands. Depending on strain rate, different types of deformation features developed, through dilation or porosity redistribution (porous flow bands), cavitation (pore channels), or tensile fracture (fracture bands). Porous flow bands have permeability values ∼4 orders of magnitude higher than undeformed rhyolite. Pore channels and fracture bands have much larger length scales, and so permeability increases dramatically in those systems. Hence, the abundance and interconnectivity of deformation features preserved in the Sandfell laccolith provided an efficient outgassing mechanism for the bulk of the intrusion. Outgassing due to viscous-brittle magma deformation during magma emplacement should therefore be considered for crystal-rich magmas, e.g., during effusive lava dome extrusion.

A NASICON-type sodium-ion conducting material was synthesized via the glass-ceramic route by investigating the zinc doped Na₂O–Al₂O₃–TiO₂–P₂O₅ system. The glasses and glass-ceramics corresponding to the formula Na_2+xAl_1-xZn_xTi(PO₄)₃ (x = 0, 0.2, 0.4, 0.6, 0.8, 1), labeled as (NAZTP-G_x) and (NAZTP-GC_x) respectively, were characterized using different techniques. Differential Scanning Calorimetry (DSC) measurements were carried out to identify the characteristic temperatures, the glass transition (T_g) and the crystallization temperature (T_c). X-ray Diffraction (XRD) analysis of the glass-ceramics confirmed the formation of a solid solution Na_2+xAl_1-xZn_xTi(PO₄)₃ NASICON phase, Theoretical calculations employing the Perdew–Burke–Ernzerhoff generalized gradients approximation (PBE-GGA) model supported the potential substitution of aluminum by zinc in the octahedral site in the NASICON-phase. Further structural insights were obtained through Infrared (IR) and Raman spectroscopies. Scanning electron microscopy (SEM) analysis revealed a distinct flower-like shape of the formed crystallites in the glass-ceramic NAZTP-GC_0.2. Electrical characterization using electrochemical impedance spectroscopy (EIS) demonstrated that the NAZTP-GC_0.2 sample exhibited the highest ionic conductivity at 300 °C, reaching 4.1 × 10⁻⁵ (Ω⁻¹ cm⁻¹) with an activation energy of 0.25 eV. The DC polarization was performed on the NAZTP-GC_0.2 glass-ceramic, revealing that the ions are the main charge carriers in the sample. This comprehensive analysis provides valuable insights into the partial zinc doping of NASICON glass-ceramics, offering potential for improved performance as solid electrolytes in various applications.

Double perovskites represent a class of materials with promising fundamental properties and a broad spectrum of potential applications. However, the wide bandgap energy in double perovskites presents a hindrance to further enhancement of their photovoltaic efficiency. In the present study, a high-pressure technique is employed to tune the bandgap energy of double perovskite Co₃TeO₆ (CTO). A giant bandgap reduction of ∼37% from 2.93 to 1.85 eV has been observed after high-pressure treatment. Subsequent synchrotron-based X-ray diffraction and Raman spectroscopy results reveal that the significant bandgap reduction of CTO accompanies a sequence of structural phase transitions during compression and decompression. Furthermore, the high-pressure phase with a smaller bandgap energy of 1.85 eV turns out to be quenchable to ambient conditions, making the quenched CTO a promising light-harvesting material for photovoltaic applications. The present results demonstrate that high pressure can represent a green and efficient technique to tune the properties of multifunctional materials and serve as a guide for searching for stable and environmentally friendly light-harvesting materials.

Spinels represent a class of ceramics with promising fundamental properties and a broad spectrum of industrial applications. However, the knowledge of pressure effects on the crystal structure of spinel is limited, which hinders their efficient synthesis using high-pressure techniques. In this paper, the effect of pressure on the crystal structure of mixed spinel ferrite Fe_0.8Ni_1.8Sb_0.4O₄ was investigated at room temperature by in situ synchrotron-based X-ray diffraction and Raman spectroscopy up to 42.19 GPa and 49.51 GPa, respectively. The X-ray diffraction results indicate that Fe_0.8Ni_1.8Sb_0.4O₄ adopts the cubic (spinel-type, space group Fd 3¯ m) structure at ambient conditions, which undergoes a pressure-induced structural transition to a monoclinic phase (space group P2₁/c), commencing at 20.83 GPa. This sluggish structural transformation turns out to be of the first-order accompanied by a volume collapse of about ∼2.2 % when completed at 29.68 GPa. A second phase transition to yet another metastable monoclinic structure with space group C2/m is observed to begin at 33.56 GPa. However, this phase transition does not complete even up to the highest pressure applied in the study. Raman results confirm that Fe_0.8Ni_1.8Sb_0.4O₄ undergoes a pressure-induced phase transition from Fd 3¯ m to P2₁/c at 27.34 GPa. The observed phase transitions are reversible, and their mechanisms are discussed in the light of the Raman spectroscopy data. The present study deepens our understanding of the high-pressure behavior of spinels, which will facilitate their industrial syntheses and a better understanding of their role in planetary interiors.

Advancing energy density, enabling lithium metal anodes, and ensuring unparalleled safety and operational reliability in lithium batteries hinge on advancing inorganic solid-state electrolytes. To overcome current impediments, we present an innovative approach that integrates glass-ceramics with a pioneering new Nasicon strategy involving molybdenum doping. In the conducted study, a series of 14Li2O-9Al2O3-38TiO2-(39-x)P2O5xMoO3 glasses, denoted as LATPMox, along with their corresponding glass-ceramics (LATPMox-GC), have exhibited a promising characteristic as solid electrolytes. X-ray diffraction (XRD) analysis confirms the formation of the novel Mo-doped Nasicon phases in the glass-ceramics, as validated by Rietveld refinement. Examination of the crystallization kinetic behavior of the glasses reveals a three-dimensional nucleation process with spherical particle growth, featuring an activation energy of 165 kJ mol-1. Transmission Electron Microscopy TEM characterization aligns crystallization behavior with crystallite and distribution within the glass matrix, resulting in a compact and dense microstructure. The structural properties of the resultant phases are examined through FT-IR, Raman spectroscopy, and TEM-SEAD analysis. Vickers indentation tests were employed to assess the microscopic fracture toughness, and both the glass and glass-ceramics materials demonstrated favorable mechanical performance. Optical characterization using UV-visible absorption highlights the reduction of Mo6+ to Mo5+, likely occupying tetrahedral sites within the crystalline lattice. Impedance spectroscopy measurement showcases the effective promotion of ionic conductivity following Mo doping, reaching a total conductivity value of 5.50 x 10-5 Omega- 1 cm- 1 along with a high lithium transference number of 0.99 at room temperature for LATPMo2.6-GC glass-ceramic. This value is larger than that of many other glass-ceramics as well as that of the well-known lithium phosphorous oxy-nitride LiPON solid electrolyte whose ionic conductivity at RT is around 2 x 10-6

The multiferroic material Pb3Mn7O15 3 Mn 7 O 15 exhibits a high resistivity arising from the orbital electrons localized around the manganese ions, which hinders its potential applications. Previous studies indicated that the resistivity of Pb3Mn7O15 3 Mn 7 O 15 was influenced by its crystal structure and the distribution of Mn ions. Consequently, pressure-induced structural change are expected to represent a viable method for tuning the resistivity and other properties of this compound. In the present study, the pressure effect on the resistivity of Pb3Mn7O15 3 Mn 7 O 15 was investigated up to 42 GPa. Furthermore, the X-ray diffraction and Raman spectroscopy techniques, along with the density functional theory calculations were employed to study the crystal structure evolution of Pb3Mn7O15 3 Mn 7 O 15 under pressure. The results demonstrate an electronic semiconductor-metal phase transition in Pb3Mn7O15, 3 Mn 7 O 15 , accompanying an irreversible orthorhombic to monoclinic phase transition. Additionally, within the orthorhombic phase, an iso-structural phase transition is observed, originating from the magnetic moments collapse of manganese cations. This study provides compelling evidence that high-pressure processing can be employed to modulate the crystal structure and functional properties of multifunctional materials.

Due to their large bandgaps, multiferroic oxides, the promising candidates for overcoming the disadvantages of metal-halide perovskites as light absorbers, have so far very limited use in solar cell applications. Previous investigations demonstrate that high pressure represents an efficient tool for tuning the bandgap of multiferroic Mn3TeO6 (MTO). However, the underlying mechanism of the giant bandgap reduction discovered in MTO remains unclear, which critically prevents the design of next-generation light absorbers. In this study, we performed in situ x-ray diffraction analyses on the structure evolution of MTO upon compression and decompression, discovering a sequence of irreversible phase transitions R(3)over bar -> C2/c -> P2(1)/n. The experimental results, supported by electronic structure calculations, show the shortening of Mn-O-Mn bonding, and, to a lower extent, the decrease in connectivity of octahedra across the phase transition, explain the giant bandgap reduction of MTO. These findings will facilitate the design and synthesis of next-generation light absorbers in solar cells.

 In this study, a new assemblage of Ediacaran metazoan fossils is reported from the basal Stahpogieddi Formation on the Digermulen Peninsula of Arctic Norway, including Anulitubus n. gen. Moczydlowska in Moczydlowska et al., Anulitubus formosus n. gen. n. sp. Moczydlowska in Moczydlowska et al., Coniculus n. gen. Moczydlowska in Moczydlowska et al., Coniculus elegantis n. gen. n. sp. Moczydlowska in Moczydlowska et al., Fistula n. gen. Moczydlowska in Moczydlowska et al., and Fistula crenulata n. gen. n. sp. Moczydlowska in Moczydlowska et al. The specimens are three-dimensionally preserved and include tubular and conical skeletons that are morphologically distinguished by their body-wall constructions, radial symmetry, polarity, segmentation, and annulation. The skeletons are interpreted to be biomineralized by primary silica based on computed micro-tomographic, petrographic, geochemical, and spectroscopic evidence of originally rigid body wall with layers of constant thicknesses, composed of opal, microcrystalline quartz, and an admixture of carbonaceous material, which differ from the host sediment mineralogy and do not show replacement or encrustation. The fossil-bearing interval immediately overlies strata of Gaskiers age and can be bracketed within 580-541 Ma, but it is estimated to be ca. 575 Ma on the basis of averaged sedimentation rates and biostratigraphic correlations with Ediacaran biota found in up-section deposits of ca. 558-555 Ma. Future new findings of such fossils in different preservation modes and further multi-collector inductively coupled plasma mass spectrometry, which shows the silicon fractionation and traces its biogenic origin versus inorganic mineralization, may corroborate the interpretation of biogenic silicification of these earliest skeletal fossils.

Glass formation and properties of manganese phosphate glasses containing both Na₂O and K₂O oxides with the general formula 49.95[xNa₂O-(1-x)K₂O]-0.1MnO₂-49.95P₂O₅ with x = 0–1 mol%, have been investigated. The vitreous samples were prepared by standard melt quenching. To get an insight into their physical properties, the density and the glass transition temperature were procedure determined. The structure of the glass was performed by Infrared, Raman, and electron spin resonance (EPR) spectroscopies. The results obtained by these techniques have allowed us to explain their structure and properties upon the variation of the chemical composition. The variation of the glass transition temperature as a function of the composition presents a minimum for the ratio Na/Na + K = 0.5. Infrared and Raman spectroscopies has identified the presence of different structural grouping units in the glassy-network. It is found that the stretching vibration ν_s(PO₂)⁻ and ν_s(P–O–P) are more sensitive to the substitution of alkali elements. EPR experiments have shown the presence of Mn²⁺ centers in the glasses. The variation of the g-factor as a function of the composition is non-linear. The non-linearity behavior of the composition dependence of T_g, vibration bending mode, and the g-factor are a fingerprint of the mixed alkali effect in the glasses under study.

A series of double-perovskite oxides Sr2Sr1-xCaxTeO6 (0 <= x <= 1) samples have been prepared in order to study the effect of composition on phase formation and the related optical properties. The objective of this work is to study the possibility of calcium insertion with different percentages since calcium in known to enhance the electrical properties. In this work a well detailed structure and phase transitions investigation of the compounds were conducted and probed by X-ray diffraction and Raman spectroscopy techniques at room temperature. Both Rietveld refinements and Raman studies revealed that two phase transitions took place as the calcium amount x increases; a first from a triclinic to a hexagonal in the range 0.1 < x < 0.25 and a second from the hexagonal to a monoclinic structure in the range 0.5 < x < 0.6. The optical absorption alpha(lambda) was also determined as a function of calcium content in the series samples using UV-vis analysis. It was revealed that a remarkable change occured in the cut-off wavelength, confirming the sequence of phase transitions C1 -> R (3) over bar m -> P2(1)/n. The optical band gap measurements showed that the triclinic Sr3TeO6 and the monoclinic Sr2CaTeO6 phases have band gap values of 2.75 and 2.81 eV, respectively. When the calcium increased to x = 0.25 (Sr2.75Ca0.25TeO6)(,) remarkable decrease of the band gap value was observed, with Eg = 2.627 eV.