Space Group R3m Research Articles

Synthesis and optimization of multifunctional BLFO/hexagonal bi-phase nanocomposite

The unique ability of multiferroic materials to display the effect of magnetoelectric coupling, ideally at room temperature, makes them an enormous source of technological application. La-doped Bi0.9FeO3 is a well-known potential applicant to be operated in multiferroic applications but, weak magnetoelectric response is one of this material's limitations. To address this issue, a series of nanocomposites is presented here by combining them with optimized SrFe12O19 contents. The SrFe12O19 has a hexagonal crystal structure with space group P63/mmc while Bi0.9La0.1FeO3 (BLFO) possesses a rhombohedral crystal structure with space group R3m, confirmed by structural analysis. A homogenous distribution of grains in bi/phase composites was seen. Using PE loops, the ferroelectric nature of this composite is determined, revealing significant polarization, remanent polarization, and efficiency. Recoverable energy and energy loss density from the charging and discharging curves demonstrate that the composite has potential for energy storage devices. Furthermore, fast switching capability of the composites make it more prominent because it consumes less energy while switching of the polarization. In addition, the magnetic properties of the composite also enhanced which make it potential candidate for utilization into multifunctional devices.

Eight mineral species in one crystal: unique zonation of polychrome tourmaline from the Krutaya vein (Malkhan pegmatite feld, Transbaikalia, Russia)

A unique unusually Mn-rich concentrically zoned polychrome crystal from the cavity of granite pegmatite of the Krutaya vein within the Malkhan pegmatite feld (Transbaikalia) is studied. It consists of six valid and two potentially new mineral species of the tourmaline supergroup. The paper provides the detailed physical, chemical and crystallographic characteristics of minerals. A Mn-richest (up to 9.6 wt. % MnO) dark brown core of the crystal is composed of fuor-tsilaisite, princivalleite and a Mn2+-F-analog of foitite. A greenish yellow intermediate zone consists of Mn-rich fuor-elbaite and darrellhenryite and is followed by a Mn-poor pink zone composed of fuor-rossmanite, rossmanite and their O2--analog. A yellowish green peripheral zone consists of late-generation Mn-bearing fuor-elbaite. The Mn content decreases, while the Li + Al content increases from the center of the dark brown zone to the margin of the crystal approximately to the middle of the pink zone, where the evolution of the tourmaline composition is inverted and this trend becomes opposite. The crystal structure of fuor-tsilaisite is refned on a single crystal extracted from this specimen, R1 = 2.4 %. The mineral is trigonal, space group R3m, a = 15.9595(1), c = 7.14164(7) A, V = 1575.31(3) A3, Z = 3.

Corkit a metatorbernit z uranového výskytu Kosobody u Jesenice

Corkite and metatorbernite occur in the supergene zone of uranium mineralization at an abandoned exploration shaft No 36 situated about 1 km NW from the village of Kosobody at Jesenice in the Rakovník District. The locality was explored for uranium in 1954–1959 and subsequently in 1970–1972 (Mrázek 1972). The mineralization is confined to discordant mm–cm thick veinlets in brecciated phyllite. The veinlets are composed of quartz, barium-rich K-feldspar, “limonite” (goethite), kaolinite, metatorbernite and corkite. The country rock is Neoproterozoic phyllite of the Teplá-Barrandian Zone (Chlupáč – Štorch 1992, Kopecký et al. 1997, Klomínský et al. 2010). The samples were collected in 2021 and studied by PXRD and in carbon-coated polished sections by EMPA. Metatorbernite forms apple-green, thin tabular to lamellar crystals 0.1–1 mm in size (Fig. 1a, b). In the thin section, it also forms more massive fillings and radiating aggregates up to several millimeters (Fig. 2a–c, Fig. 3a). EMPA showed good agreement with the theoretical formula. The content of barium fluctuates in the range of 0.0–5.51 wt. % BaO, which corresponds up to 36 mol. % of metauranocircite component. The mean empirical formula is: (Cu0.79Ba0.12Ca0.03) (UO2)2.03(PO4)1.98 · 8 H2O, see Table 1. The lattice parameters calculated for the Space Group P4/n: a = 6.9647(8) A, c = 17.322(2) A, V = 840.2(2) A3 are in good agreement with published data (compare Table 2). Corkite forms isometric or irregular accumulations up to 1 mm in size of yellow colour, which are mostly brown cloudy, intergrown ith metatorbernite and are often surrounded by aggregates of “limonite” (goethite) and kaolinite flakes (Fig. 2a–c). In BSE, corkite aggregates show irregular darker and lighter domains (Fig. 3b). Lighter domains have slightly higher Pb contents, otherwise the differences in chemical composition are negligible. To calculate the empirical formula, the numbers of atoms were normalized to the sum T-site elements = 2. The mean empirical formula: (Pb0.99U0.04)(Fe2.85Al0.26) [(PO4)1.46 (SO4)0.49] (OH)6, displays a significant predominance of P over S. The data are thus plotted near the corkite – kintoreite boundary in the ternary P – As – S diagram (Fig. 4). The Al, which partly replaces Fe3 , indicates 4–12 mol. % of isomorphic admixture of hinsdalite, ideally PbAl3(PO4)(SO4)(OH)6. There is also low but omnipresent content of uranium (0.03–0.05 U apfu, see Table 3), which was not reported among minerals of the crandallite group (Fig. 5). The lattice parameters a = 7.265(3) A, c = 16.87(1) A, V = 771.5(6) A3, calculated for the Space Group R3m, are in the agreement with the published data (compare Table 4).

Study of the amorphous and crystalline states in Ge(Te1-xSex) thick films (x = 0, 0.50) by in situ temperature-dependent structural analyses

As-deposited and unencapsulated GeTe1-xSex (x = 0, 0.5) 3-μm-thick amorphous films on Si(001) were obtained via the thermal co-evaporation technique. The crystallization and the structure of these phase change materials were examined using in situ temperature-dependent X-ray diffraction (XRD) and grazing-incidence fluorescence X-ray Absorption Near Edge Structure (XANES) in isochronal annealing conditions under nitrogen flow. The results show that the onset temperature of crystallization is highly sensitive to the substitution of the Te atoms by the Se ones and that the rhombohedral structure, with the space group R3m, is the one that crystallized for both samples without Ge or Te rejection. Moreover, the local order around the Ge and Se atoms, probed by Ge and Se K-edge XANES analyses, presents clear modifications from the amorphous state to the crystalline one expecting a Ge four-fold and a Se two-fold coordination in the amorphous state, with an increase of the local disorder with the Se substitution (x = 0.5).

Edge Functionalization of Bulk γ-Graphyne Facilitates Mechanical Exfoliation and Modulates the Mode of Sheet Stacking.

We have successfully achieved selective and efficient functionalization of sheet edges in microcrystalline multilayer γ-graphyne through two methods: cross-coupling with residual bromide edge groups and copper-catalyzed azide-alkyne cycloaddition (CuAAC) with edge terminal alkyne groups. This modification significantly enhances the ease of mechanical exfoliation and dispersibility of the sheets of γ-graphyne. Specifically, C18-grafted γ-graphyne forms stable dispersions in compatible organic solvents, allowing for the imaging of atomically thin layers of γ-graphyne for the first time. Additionally, we have discovered that phenylacetylide edge groups alter the preferred stacking mode of γ-graphyne sheets. Few-layer flakes of Ph-edge γ-graphyne exhibit a preference for the R3m space group, contrasting with the aperiodic stacking of Br-edge γ-graphyne. These results open the door for scalable exfoliation of few-layer flakes of γ-graphyne with a high aspect ratio, enabling potential applications in carbon electronics.

Transistors with ferroelectric ZrXAl1−XOY crystallized by ZnO growth for multi-level memory and neuromorphic computing

Ferroelectric (FE) field-effect transistors are interesting for their non-destructive readout characteristic and energy efficiency but are difficult to integrate on silicon platforms. Here, FE ZrXAl1−XOY (ZAO) is demonstrated by compressive strain in contact with ZnO. The metal-ferroelectric-semiconductor-metal capacitor exhibits a substantial remnant polarization of 15.2 µC cm−2, along with a bowknot-like anti-clockwise hysteresis in the capacitance curves. The FE-ZAO gated ZnO thin-film transistor presents a large memory window (3.84 V), low subthreshold swing (55 mV dec−1), high ION/IOFF ratio (≈108), and low off-state current (≈1 pA). The grazing incidence X-ray diffraction and scanning transmission electron microscopy analyses reveal the ferroelectric rhombohedral phase (space group R3m) in the nanocrystal ZAO, containing an angle of ≈71.7° between the [111] and [11-1] directions with d111-spacing of 3.037 Å and d11-1-spacing of 2.927 Å. Finally, the memory and neuromorphic applications are analyzed by demonstrating multi-level memory and synaptic weight performance with a high learning accuracy of 91.82%.

Phase structure of the ceramic samples of the BiScO3–PbTiO3–PbMg⅓Nb⅔O3 system near the morphotropic phase boundary studied by the Rietveld method

Abstract An X-ray diffraction study of ceramic samples of the BiScO3–PbTiO3–PbMg⅓Nb⅔O3 system with compositions close to the morphotropic phase boundary was carried out at room temperature. The existence of wide areas of solid solutions has been established. The symmetry of the PbTiO3-based solid solutions is tetragonal (space group P4mm). The symmetry of the PbMg⅓Nb⅔O3-based solid solutions is cubic (space group Pm3‾m). Near the BiScO3 side, the solid solutions are rhombohedral (space group R3m). During the morphotropic phase transition from the cubic solid solutions to the tetragonal ones, additional phases appear. If a tetragonal phase prevails ((1 − 2x)BiScO3–xPbTiO3–xPbMg⅓Nb⅔O3 x = 0.46; (1 − 2x)BiScO3–1.1xPbTiO3–0.9xPbMg⅓Nb⅔O3 x = 0.45 and 0.42), a satisfactory model is a model with a minority cubic phase (space group Pm3‾m). If a cubic phase prevails ((1 − 2x)BiScO3–1.1xPbTiO3–0.9xPbMg⅓Nb⅔O3 x = 0.39 and 0.36; (1 − 2x)BiScO3–0.8xPbTiO3–1.2xPbMg⅓Nb⅔O3 x = 0.4), a model with a minority monoclinic phase (space group Cm) or with two minority phases: tetragonal (space group P4mm) and monoclinic (space group Cm) is satisfactory.

Van der Waals Epitaxial Growth of One-Unit-Cell-Thick Ferroelectric CuCrS2 Nanosheets.

Ferroelectric two-dimensional (2D) materials with a high transition temperature are highly desirable for new physics and next-generation memory electronics. However, the long-range polar order of ferroelectrics will barely persist when the thickness reaches the nanoscale. In this work, we synthesized 2D CuCrS2 nanosheets with thicknesses down to one unit cell via van der Waals epitaxy in a chemical vapor deposition system. A combination of transmission electron microscopy, second-harmonic generation, and Raman spectroscopy measurements confirms the R3m space group and noncentrosymmetric structure. Switchable ferroelectric domains and obvious ferroelectric hysteresis loops were created and visualized by piezoresponse force microscopy. Theoretical calculation helps us understand the mechanism of ferroelectric switching in CuCrS2 nanosheets. Finally, we fabricated a ferroelectric memory device that achieves an on/off ratio of ∼102 and remains stable after 2000 s, indicating its applicability in novel nanoelectronics. Overall, 2D CuCrS2 nanosheets exhibit excellent ferroelectric properties at the nanoscale, showing great promise for next-generation devices.

Organic Polar Crystals, Second Harmonic Generation, and Piezoelectric Effects from Heteroadamantanes in the Space Group R3m.

Polar crystalline materials, a subset of the non-centrosymmetric materials, are highly sought after. Their symmetry properties make them pyroelectric and also piezoelectric and capable of second-harmonic generation (SHG). For SHG and piezoelectric applications, metal oxides are commonly used. The advantages of oxides are durability and hardness - downsides are the need for high-temperature synthesis/processing and often the need to include toxic metals. Organic polar crystals, on the other hand, can avoid toxic metals and can be amenable to solution-state processing. While the vast majority of polar organic molecules crystallize in non-polar space groups, we found that both 7-chloro-1,3,5-triazaadamantane, for short Cl-TAA, and also the related Br-TAA (but not I-TAA) form polar crystals in the space group R3m, easily obtained from dichloromethane solution. Measurements confirm piezoelectric and SHG properties for Cl-TAA and Br-TAA. When the two species are crystallized together, solid solutions form, suggesting that properties of future materials can be tuned continuously.

Structural stability and polarization analysis of rhombohedral phases of HfO2

Since the experimental observation of a rhombohedral phase of hafnium oxide, there remains controversy over whether this phase belongs to the R3 or R3m space group. Moreover, the origin of polarization in these two rhombohedral phases has not been comparatively elucidated. Here, we present a theoretical study comparing the relative stability and ferroelectricity of the R3 and R3m phases of HfO2, representing two potential forms of heavily Zr-doped ferroelectric thin films of hafnia found recently. We comprehensively investigate their structural stability and polarization response under in-plane compressive strain. A phase transition from R3 to R3m is discovered under biaxial compressive strain. The direction and magnitude of polarization in both phases can be tuned by strain. Through symmetry mode analysis, we elucidate the improper nature of ferroelectricity. These findings may advance understanding of ferroelectricity in hafnia thin films.

Correlation of magnetic and dielectric relaxation to perovskite/spinel structural phase transition in Bi0.9La0.1FeO3–Fe3O4 bi-phase composites

Nanocomposites are widely investigated nowadays due to their vast applications in multifunctional devices. La-doped Bi0.9FeO3 is considered as potential candidate to be utilized in multiferroic applications. However, limitations of this composition include weak magnetic and magnetoelectric response. To overcome weak magnetic response of this material, a series of nanocomposite samples is presented here by combining it with optimized Fe3O4 contents. X-ray diffraction patterns confirm the cubic structure of Fe3O4 belonging to space group Fd3‾m and the rhombohedral-type perovskite crystal structure of Bi0.9La0.1FeO3 having space group R3m. Field emission scanning electron microscopy reveals spherical shapes of nanograins. High dielectric constant with fewer energy losses revealed for pure Bi0.9La0.1FeO3 composition, while saturation magnetization and remanent magnetization were increased with the addition of Fe3O4 phase into Bi0.9La0.1FeO3. Enhanced magnetic properties with moderate dielectric properties of 0.6Bi0.9La0.1FeO3+0.4Fe3O4 make it a prominent and potential candidate to be utilized in memory storage devices.

Physical properties and crystal structure of near end-member oxy-dravite from the Beluga occurrence, Nunavut territory, Canada

AbstractOxy-dravite, ideally Na(Al2Mg)(Al5Mg)(Si6O18)(BO3)3(OH)3(O), was found in a composition near its ideal end-member at the Beluga occurrence, Nunavut territory, Canada. It occurs in retrograde albite–muscovite–corundum–calcite domains in a calc-silicate rock. This uncommon oxy-dravite occurs as dark brown, equant to short-prismatic, idiomorphic crystals with vitreous lustre and up to ca. 4 × 3 cm in size. The oxy-dravite is optically uniaxial (–), with ω = 1.6453(5) and ɛ = 1.6074(18); its calculated density is 3.069 g.cm–3 with a compatibility index of 0.016. The Beluga oxy-dravite has trigonal symmetry, space group R3m with a = 15.9121(2) Å, c = 7.1788(10) Å, V = 1574.12(5) Å3 and Z = 3. The crystal structure was refined to R1 = 1.45 using 1613 unique reflections. The empirical crystal-chemical formula is X(Na0.88Ca0.08□0.03K0.01)Y(Al1.49Mg1.31Fe0.15Ti0.04Zn0.01)Z(Al5.42Mg0.58)T(Si5.84Al0.16O18)B(BO3)3V(OH2.95O0.05)W(O0.84OH0.01F0.15).Oxy-dravite in nature commonly occurs in a solid solution with foitite, schorl and oxy-schorl. At the Beluga occurrence, its minor contents of Al, vacancy [□], and Ca are most likely compensated by (□Al)(NaR2+)–1 and (CaMg)(NaAl)–1 exchanges of the oxy-magnesio-foitite and magnesio-lucchesiite components. The Beluga occurrence of oxy-dravite is characterised by an Mg-rich environment related to a metamorphic overprint of the original sedimentary sequence. This sequence of marine dolomitic argillaceous marl was influenced by (B,Cl)-rich fluids, probably proximally-derived from mineral breakdown reactions in the calc-silicate during the retrograde stage of metamorphism. The locality is a rare example of a tourmaline + corundum assemblage.

Experimental and computational study of binary transition metal oxides NaNi1/2 X1/2 O2 (X=Cr, Fe, Co and Cu) for energy storage applications

For novel applications as cathodes in sodium-ion batteries, layered transition metal oxides have been reported to have an appropriate voltage window that results higher specific capacity and energy density. In the present work, a series of binary layered transition metal oxides: NaNi1/2Cr1/2O2, NaNi1/2Fe1/2O2, NaNi1/2Co1/2O2, and NaNi1/2Cu1/2O2 were prepared using sol-gel technique. XRD analysis confirmed that all the synthesized materials stabilize a hexagonal structure with an R3m space group. SEM micrographs showed the formation of well-separated particles of varying shapes. FTIR spectra indicated the presence of metal oxygen absorption bands. Using density functional theory (DFT), crystal structure was generated using the lattice parameters worked out using XRD. The spin polarized electronic band structures and density of states (DOS) computed for all four compounds revealed half metallic character. Average intercalation voltages (AIV) were calculated theoretically from the total energies of the optimized compounds and their de-sodianted phases. Volume changes were also calculated to study its minimal values for the compounds, to identify them as of good structural stability. Both experimental findings and theoretical calculations show that the investigated binary layered transition metal oxides are suitable cathode materials for coin cell fabrications.

Dutrowite, Na(Fe2+2.5Ti0.5)Al6(Si6O18)(BO3)3(OH)3O, a new mineral from the Apuan Alps (Tuscany, Italy): the first member of the tourmaline supergroup with Ti as a species-forming chemical constituent

Abstract. The new tourmaline supergroup mineral dutrowite, Na(Fe2.52+Ti0.5)Al6(Si6O18)(BO3)3(OH)3O, has been discovered in an outcrop of a Permian metarhyolite near the hamlet of Fornovolasco, Apuan Alps, Tuscany, Italy. It occurs as chemically homogeneous domains, up to 0.5 mm, brown in colour, with a light-brown streak and a vitreous lustre, within anhedral to subhedral prismatic crystals, up to 1 mm in size, closely associated with Fe-rich oxy-dravite. Dutrowite is trigonal, space group R3m, with a=15.9864(8), c=7.2187(4) Å, V=1597.68(18) Å3, and Z=3. The crystal structure was refined to R1=0.0257 for 1095 unique reflections with Fo>4σ (Fo) and 94 refined parameters. Electron microprobe analysis, coupled with Mössbauer spectroscopy, resulted in the empirical structural formula X(Na0.81Ca0.20K0.01)Σ1.02 Y(Fe1.252+Mg0.76Ti0.56Al0.42)Σ3.00 Z(Al4.71Fe0.273+V0.023+Mg0.82Fe0.182+)Σ6.00 T[(Si5.82Al0.18)Σ6.00O18] (BO3)3O(3)(OH)3O(1)[O0.59(OH)0.41]Σ1.00, which was recast in the empirical ordered formula, required for classification purposes: X(Na0.81Ca0.20K0.01)Σ1.02 Y(Fe1.432+Mg1.00Ti0.56)Σ3.00 Z(Al5.13Fe0.273+V0.023+Mg0.58)Σ6.00 T[(Si5.82Al0.18)Σ6.00O18] (BO3)3V(OH)3 W[O0.59(OH)0.41]Σ1.00. Dutrowite is an oxy-species belonging to the alkali group of the tourmaline supergroup. Titanium is hosted in octahedral coordination, and its incorporation is probably due to the substitution 2Al3+ = Ti4+ + (Fe,Mg)2+. Its occurrence seems to be related to late-stage high-T/low-P replacement of “biotite” during the late-magmatic/hydrothermal evolution of the Permian metarhyolite.

Growth and thermal properties of InSe crystal by using the ground simulation apparatus of China space station

Indium selenide (InSe) semiconductor crystal was grown by using the ground simulation apparatus of China space station in this work. The furnace was controlled at 715 °C and the temperature gradient for crystal growth was ∼30 °C/cm. The as-grown InSe crystalizes in γ-phase with space group of R3m. The average etching pits density (EPD) is estimated to be about 104/cm2. Thermal analysis indicates a positive thermal expansion at 30–500 °C and no volatilization occurred even as high as 1000 °C. This work not only establishes a reliable process for preparing large-sized InSe single crystal but also creates a foundation for further work in outer space in the future.

Facile auto-combustion synthesis of nanocrystalline BaCoFe6O11-Structural and Optical properties

The BaCoFe6O11 (Barium cobalt hexairon (III) oxide) is efficiently synthesized by modified single-step auto-ignition combustion route. The sample crystallized under trigonal structure with a space group R3-m with hexagonal axes obtained from XRD. The XRD determined crystallite size is 10 nm, which is corroborated by the Hall-Williamson plot and Modified Scherrer technique. Fourier transform infrared spectroscopy is used to identify the functional group and confirm the phase purity of the sample. Transmission electron microscopy images indicate the sample’s nanocrystalline structure. Additionally, FE-SEM is used to analyse the surface morphology of the material. The optical band gap energy are estimated by using UV–visible spectroscopy and also calculated by Tauc’s plot and Kubelka-Munk function. Photoluminescence emission peaks in the visible region as well as band gap energy values, confirms the sample’s practicality in optoelectronic devices.

Kuvaevite, Ir5Ni10S16, a New Mineral Species, Its Associations and Genetic Features, from the Sisim River Placer Zone, Eastern Sayans

Abstract —Kuvaevite, ((Ir,Rh)5(Ni,Fe,Cu)10S16), forms small grains (up to 20 µm across) in globular inclusions hosted by grains of Os–Ir–(Ru) alloys (up to 0.5 mm) in ore occurrences along the Ko River in the Sisim placer zone, Eastern Sayans. Rh-bearing pentlandite or oberthürite (or both), the minerals of the laurite-erlichmanite series and Pt–(Pd)–Fe alloys are the main associated minerals. Kuvaevite is gray to brownish gray in color in reflected light. Its bireflectance is weak to absent. It is slightly pleochroic in gray to light brown shades, and slightly anisotropic, from gray to light yellow shades. Its calculated density is 6.37 g/cm3. According to results of microprobe analyses (n = 3) carried out using wavelength-dispersive spectrometry, WDS, the composition of kuvaevite is: Cu 5.94 (4.39–6.89), Ni 13.95 (13.80–14.24), Fe 10.95 (10.18–11.97), Co 0.07 (0.06–0.10), Ir 32.38 (32.19–32.73), Rh 7.27 (7.22–7.31), Pt 1.91 (1.67–2.06), Os 0.05 (0–0.09), Ru 0.05 (0.04–0.05), S 27.06 (26.77–27.41), total 99.63 wt.%. The empirical formulae calculated using the mean results of analyses are: (Ir3.22Rh1.35Pt0.19Ru0.01Os0.01)Σ4.78(Ni4.54Fe3.75Cu1.79Co0.02)Σ10.10S16.13 (WDS) and (Ir3.23Rh1.43Pt0.25)Σ4.91(Ni4.49Fe3.57Cu1.86Co0.06)Σ9.98S16.11 (SEM/EDS; n = 56). These are based on a total of 31 atoms according to structural data obtained for torryweiserite, the rhodium-dominant analogue. Kuvaevite forms solid-solution series with torryweiserite, tamuraite and ferrotorryweiserite, all these being isostructural. The symmetry of kuvaevite was determined using the synchrotron Laue microdiffraction; the results are in good agreement with the trigonal crystal system and give the following unit-cell parameters: a = 7.079(5) Å, c = 34.344(12) Å, V = 1490(2) Å3; Z = 3. The ratio c/a is 4.852. The probable space-group, R3m (#166), is based on structural results for torryweiserite. The strongest eight reflections in the X-ray diffraction pattern derived from the microdiffraction study [d in Å(hkl) (I)], are the following: 3.0530(201)(43), 3.0103(216)(100), 2.9962(1010)(53), 2.7991(205)(50), 2.4946(208)(31), 1.9208(3110)(41), 1.7697(410)(73), 1.7582(2016)(66). The results of the electron backscatter diffraction study (EBSD) of two kuvaevite crystals are well–indexed based on the R3m space group. Kuvaevite and related sulfides significantly vary in composition in the Ko River placer, in the entire Sisim zone, and in some other ore occurrences worldwide. Associations of platinum-group minerals observed in ore occurrences at Ko River and in the Sisim zone seem to be genetically related to bedrock zones of chromite-bearing ultramafic rocks (serpentinites) of the Lysanskiy complex. Kuvaevite and other minerals present in the polymineralic inclusions, hosted by Os–Ir–(Ru) alloys, formed from droplets of residual melt. This melt accumulated the “incompatible” elements, which could not be incorporated into the structure of the host alloy, including lithophile elements, chalcogens (S, Te), semimetals (As, Sb, Bi), base metals (Fe, Ni, Cu), as well as relatively low-temperature PGE species (Pt, Pd) and Rh. There are local data on metastable crystallization and undercooling of the silicate melt, as well as effective differentiation and fractionation of S and ore components during the crystallization of these inclusions. Kuvaevite is named after O.M. Kuvaev (1934–1975), a prominent geologist, geophysicist and writer.

Synthesis, Structural and Electrochemical Properties of Sodium Transition Metal Fluorosulfate Cathodes for Na-Ion Batteries

The development of low-cost and sustainable rechargeable batteries is attractive for storing energy from renewable sources. At present, the expansion of Na-ion batteries (NIBs) serves as an appealing solution from the perspective of both raw material abundance as well as the cost in comparison with the existing Li-ion batteries.1 However, the energy densities of NIBs are lower compared to their Li-ion counterparts due to thermodynamic reasons. To address this issue, researchers have turned their attention towards the development of high energy density cathodes, such as Na3V2(PO4)2F3 and Na3V2(PO4)3-type materials,2 in which the operation of multi-redox couples render high storage capacities. Moving forward, the replacement of PO4 3- by SO4 2- provides higher intercalation voltages (due to inductive effect), thereby further improving the overall energy density of cathode. 3 The inclusion of fluoride into the sulphate based polyanionic frameworks will help to increase the operating voltage through inductive effects.4 This will enhance cationic mobility by reducing electrostatic interactions along conduction channels, thereby, lead to increase in cell capacity.Herein, we report synthesis, structural and electrochemical properties of two classes of sodium transition metal fluorosulfates, namely Na3MF2(SO4)2 and jarosites NaM3(SO4)2(OH/F)6 (M= V and Mn etc.,). The Na2VF3(SO4)2 framework consists of chains of trans-VO2F4 octahedra linked to each other via vertex sharing of F atoms and bridged by SO4 tetrahedron as adjacent pairs. 5 Jarosite is a natural mineral to be found in acidic and sulfate-rich environments with a general formula of AM3(SO4)2(OH)6, where A = K+, Na+, and NH4 + and M = Fe3+, Cr3+, V3+, Ga3+, Al3+, and In3+. Jarosite crystals stabilize in a trigonal system with space group R3m. The structure is composed of 2D uneven layers formed by linkage of transition metal octahedra [MO2(OH)4] and sulfate tetrahedra (SO4), that are stacked along the c direction. 6 We unveil the details of growth mechanism of these materials in hydro- and solvo-thermal conditions using X-ray diffraction and microscopy techniques. Further, the mechanism of electrochemical (de)sodiation reactions in these materials will be presented using galvanostatic cycling and in-operando XRD measurements.

Study on Structural, Electrical and Magnetical Properties of Zn Doped CuAlO2 Ceramics

To improve the properties of CuAlO2 thin films, the preparation of CuAlO2 ceramics with excellent properties is an important prerequisite, and the optimization of ceramic properties is often achieved by doping. Zn-doped CuAlO2 ceramics were prepared by the solid phase sintering method. The structural, electrical and magnetic properties of Zn-doped CuAlO2 ceramics were systematically studied. The results show that the crystal structure of the as-sintered Zn-doped CuAlO2 was rhombohedral, space group R3m. Grain size of samples grew with the amount of Zn increases, which is related to the enhancement of CuAl2O4 phases in the sample ceramics. The density of doped ceramics changed when increasing Zn-doping concentration compared to undoped ceramics. It reached a minimum 0.96 g/cm3. The resistivity of Zn-doped CuAlO2 ceramic samples climbed with the increase of Zn content, and it can reach 59.6 Ω•cm at 10 mol%. The ferromagnetic behavior was enhanced with increasing the Zn concentration.

Electrical Study of PVP/LiCo<sub>1-x</sub>Zn<sub>x</sub>O<sub>2</sub> Nanoparticles Embedded Nanofibers

Energy storage devices are the demand of the new era for flexible portable electronics. Considering the importance of renewable energy and environmental issues. We utilized LiCo1-xZnxO2 (x=0.0, 0.1) nanoparticles with an average crystallite size of 31-45nm that were embedded in nanofibers formed by the electrospinning technique. Sol-gel techniques were used to make them. PVP polymer was used as a binder to support the backbone frame of the nanofibers. We have characterized our synthesized material to examine its structural, morphological, and electrical properties. XRD of synthesized material tells us about the rhombohedral structure of the R3m space group symmetry. FTIR spectroscopy was used to study the functional groups and vibrations in synthesized material. SEM results confirmed the formation of nanoparticles embedded in nanofibers. In AC analysis, we have discussed dielectric constant, tangent loss, and AC conductivity. The electrical properties of synthesized LiCo1-xZnxO2 (x=0.0, 0.1) nanofibers were studied in a frequency range of 100Hz to 3MHz and found that AC conductivity is high of nanoparticles embedded nanofibers of LiCo0.9Zn0.1O2 i.e., 4.2 x10-5 (S/m) that plays a crucial role for the supercapacitors and as a cathode material in Lithium-ion batteries(LIBs).