Journal of Solid State Chemistry最新文献_第2页

Formation enthalpy of B2 and related phases of Al–Cu–Fe system Al-Cu-Fe体系中B2及相关相的生成焓

IF 3.5 3区化学 Q2 CHEMISTRY, INORGANIC & NUCLEAR

Journal of Solid State Chemistry

Pub Date : 2025-12-08 DOI: 10.1016/j.jssc.2025.125774

I.A. Tomilin , V.V. Tcherdyntsev , T.A. Sviridova , V.A. Sudarchikov , S.S. Alexandrova , E.V. Medvedeva

The standard enthalpies of formation of binary and ternary alloys of the Al–Cu–Fe system were obtained experimentally by the high-temperature solution calorimetry. The results are in good agreement with the theoretical and experimental literature data. The minimum enthalpies were observed at the iron contents of 60–70 at. %. This was attributed to the D0₃-type ordering characteristic of alloys with compositions close to AlFe₃. Based on the constructed enthalpy diagram, it was proposed that in the B2-ordered solid solutions of the Al–Cu–Fe system, the region with a tendency to ordering with the formation of complex superstructures shifts toward higher aluminum concentrations compared to the binary Al–Fe system. The analysis of the B2 phase lattice parameter concentration dependences showed that the lattice parameter in most cases increase as the Fe/Cu atomic ratio approached unity. It was supposed that one of the factors determining the lattice parameter is the influence of the chemical repulsion forces between Fe and Cu atoms in the crystalline structure. A comparison of the enthalpies of formation of the quasicrystalline phase of the Al–Cu–Fe system with the crystalline phases of the same system showed that the strength of the chemical bond in the quasicrystalline alloy of the system under study is close to that for solid solutions with the B2 structure with the Al/Cu ratio of 2.3–2.5 and an iron content below 50 at. %. This similarity may be due to the fact that the B2 phase of the system under study, from the point of view of local atomic configurations, can be considered as an approximant of the quasicrystalline phase.

用高温溶液量热法测定了Al-Cu-Fe体系二元和三元合金的标准生成焓。计算结果与理论和实验文献数据吻合较好。在铁含量为60 ~ 70 at时，观察到最小焓。%。这是由于成分接近AlFe3的合金具有d03型有序特征。根据构建的焓图，提出了在b2有序的Al-Cu-Fe体系固溶体中，与二元Al-Fe体系相比，随着复杂上层结构的形成，具有有序倾向的区域向铝浓度更高的方向转移。对B2相晶格参数浓度依赖性的分析表明，在大多数情况下，随着Fe/Cu原子比趋于1，晶格参数增大。推测晶格参数的决定因素之一是晶体结构中铁和铜原子之间的化学斥力的影响。Al - Cu - fe体系准晶相的生成焓与同类体系的晶相的生成焓比较表明，该体系准晶合金的化学键强度接近于Al/Cu比为2.3 ~ 2.5、铁含量低于50 at的B2结构固溶体的化学键强度。%。这种相似性可能是由于所研究体系的B2相，从局部原子构型的角度来看，可以被认为是准晶相的近似值。

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引用次数: 0

Glycerol as a green solvent for synthesis of AgBiS2 nanoparticles: Application as dye-sensitized solar cells 甘油作为合成AgBiS2纳米颗粒的绿色溶剂：在染料敏化太阳能电池中的应用

IF 3.5 3区化学 Q2 CHEMISTRY, INORGANIC & NUCLEAR

Journal of Solid State Chemistry

Pub Date : 2025-12-06 DOI: 10.1016/j.jssc.2025.125769

Swarada G. More , Almas M. Mujawar , Pankaj K. Bhujbal , Sandesh R. Jadkar , Habib M. Pathan , Sanjay R. Gadakh

It is highly demanding to obtain nano-sized particles at room temperature using a green synthesis protocol. Considering the green approach, for the first time, we have synthesized silver bismuth sulfide nanoparticles (AgBiS₂ NPs) using glycerol as a solvent at room temperature. This protocol uses greener solvent and eliminates the requirement of elevated temperature to produce pure cubic phase AgBiS₂ nanoparticles with a size in the range of 20–90 nm. The synthesized AgBiS₂ nanoparticles are characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, high-resolution transmission electron microscopy (HRTEM), and scanning electron microscopy (SEM) techniques. The band gap of AgBiS₂ NPs is calculated by ultraviolet (UV) spectroscopy, and it is found to be around 1.2 eV, which confirms its potential to be used as an absorber layer in a solar cell. Then, AgBiS₂ NPs film of different thicknesses was prepared by the spin coating method and used in Dye-sensitized solar cell (DSSC). The film with five layers of spin coating shows the best optimized performance with fill factor (FF) 36.99 %, open circuit voltage (V_oc) 0.535 V, short-circuit current density (J_sc) 4.96 mA/cm² and efficiency (η) 0.98 %.

使用绿色合成方案在室温下获得纳米级颗粒的要求很高。考虑到绿色途径，我们首次在室温下以甘油为溶剂合成了硫化铋银纳米颗粒（AgBiS2 NPs）。该方案使用更环保的溶剂，消除了生产尺寸在20-90纳米范围内的纯立方相AgBiS2纳米颗粒的高温要求。采用x射线衍射（XRD）、x射线光电子能谱（XPS）、拉曼光谱、高分辨率透射电子显微镜（HRTEM）和扫描电子显微镜（SEM）等技术对合成的AgBiS2纳米颗粒进行了表征。通过紫外光谱计算AgBiS2 NPs的带隙，发现其带隙约为1.2 eV，证实了其作为太阳能电池吸收层的潜力。然后，采用自旋镀膜法制备不同厚度的AgBiS2 NPs薄膜，并将其应用于染料敏化太阳能电池（DSSC）中。五层自旋镀膜性能最佳，填充系数（FF）为36.99%，开路电压（Voc）为0.535 V，短路电流密度（Jsc）为4.96 mA/cm2，效率（η）为0.98%。

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引用次数: 0

Problems of synthesis and ordering of the medium-entropy perovskite PbSc1/4In1/4Nb1/4Ta1/4O3 中熵钙钛矿PbSc1/4In1/4Nb1/4Ta1/4O3的合成与排序问题

IF 3.5 3区化学 Q2 CHEMISTRY, INORGANIC & NUCLEAR

Journal of Solid State Chemistry

Pub Date : 2025-12-05 DOI: 10.1016/j.jssc.2025.125767

Ivan G. Sheptun , Inna V. Lisnevskaya , Elena A. Reshetnikova , Olga Yu. Grapenko , Elizaveta S. Kulikova , Alexey Yu. Seregin , Victoria A. Shuvaeva , Nikita V. Ter-Oganessian

A comparative study of the medium-entropy perovskite PbSc_1/4In_1/4Nb_1/4Ta_1/4O₃ (PSINT), synthesized by solid-state reaction, melt-solution (flux) crystallization, and the gel (sol–gel) route, was carried out. High-resolution synchrotron X-ray diffraction was employed to ensure methodological consistency across all samples. In the solid-state route, prolonged annealing at 800 °C for 100 h completely eliminates the residual pyrochlore impurity, yielding a single-phase cubic perovskite (Pm–3m, a = 4.09538(5) Å). Flux growth produces two crystal types—perovskite and pyrochlore—with compositions deviating from the nominal due to cation segregation in the melt and partial B-site ordering. Superstructure reflections, corresponding to double and triple perovskite cell with a = 4.08661(14) Å, are observed at the diffraction patterns. These reflections presumably originate from mixed 1:1 and 1:2 B-site cation ordering. The gel route proceeds through a transient pyrochlore intermediate that transforms into perovskite near 800 °C. Stabilization of the perovskite structure has been achieved due to an optimum fluorine concentration of about 0.04 at.% per mole of PSINT, whereas reduction of this value, caused by fluorine depletion at higher temperatures (900–1100 °C), leads to regeneration of the pyrochlore phase. The gel-derived PSINT shows the lowest atomic displacement parameters and the highest structural homogeneity. These results provide new information on the influence of synthesis environment on the characteristics of medium-entropy oxide perovskites.

对采用固相反应、熔体-溶液（助熔剂）结晶和凝胶（溶胶-凝胶）法制备中熵钙钛矿PbSc1/4In1/4Nb1/4Ta1/4O3 （PSINT）进行了对比研究。采用高分辨率同步加速器x射线衍射确保所有样品的方法一致性。在固相方法中，800℃下延长退火100 h完全消除了残余的焦绿石杂质，得到单相立方钙钛矿（Pm-3m, a = 4.09538(5) Å）。熔剂生长产生钙钛矿和焦绿石两种晶体类型，由于熔体中的阳离子偏析和部分b位有序，它们的成分偏离了标称。在衍射图上观察到双层和三重钙钛矿电池的上层结构反射，对应于a = 4.08661（14） Å。这些反射可能源于混合1:1和1:2的b位阳离子排序。凝胶途径通过一种瞬态焦绿盐中间体，在800°C附近转化为钙钛矿。由于最佳氟浓度约为0.04 at，钙钛矿结构得以稳定。而在较高温度（900-1100°C）下氟耗尽导致该值降低，导致焦绿盐相再生。凝胶衍生的PSINT具有最低的原子位移参数和最高的结构均匀性。这些结果为合成环境对中熵氧化物钙钛矿性质的影响提供了新的信息。

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引用次数: 0

Terephthalate-based covalent organic framework as high-performance anode material for sodium-ion storage and full cell 基于对苯二甲酸酯的共价有机骨架作为钠离子存储和全电池的高性能负极材料

IF 3.5 3区化学 Q2 CHEMISTRY, INORGANIC & NUCLEAR

Journal of Solid State Chemistry

Pub Date : 2025-12-04 DOI: 10.1016/j.jssc.2025.125768

Kun Chu , Tingting Cheng , Taixing Zhu , Zhengyu Huang , Guichao Liu , Shaowen Wu , Ming-Ming Hu , Shihua Dong

Carboxylate-based anode materials have substantial application potential for sodium-ion batteries (SIBs) used for large scale electrochemical energy storage owing to their advantages of high specific capacity, cost-effective and sustainability. Covalent organic frameworks (COFs) are able to improve the cycling stability and rate performance of small organic compound due to their designable compositions and stable porous structures. Herein, terephthalic acid (TPA) was reacted with hexachlorocyclotriphosphazene (HCCP) via polycondensation to prepare TPA-HCCP COF. The prepared COF anode exhibits a low discharge potential of 0.26 V, high reversible specific capacity of 120 mA h g⁻¹ and good rate performance due to its stable microporous framework with abundant accessible active sites. Sodium-ion storage kinetics of the COF is a combination process of diffusion and capacitance due to the electroactive sites of CO and coordinate sites of N for sodium-ions. Full cell was fabricated using Na₄Fe₃(PO₄)₂(P₂O₇) (NFPP) as cathode material to evaluate the practical application potential of the COF anode at wide operation temperature. The NFPP||COF full cell exhibited a high mean voltage of 3.0 V and delivered a specific discharge capacity of 118 mA h g⁻¹. This research provides an effective strategy of designing and preparing terephthalate-based COF anode material and validates its practical application potential for SIBs.

羧酸盐基负极材料具有高比容量、高性价比和可持续性等优点，在大规模电化学储能钠离子电池中具有很大的应用潜力。共价有机框架（COFs）由于其可设计的组成和稳定的多孔结构，能够提高小有机化合物的循环稳定性和速率性能。本文以对苯二甲酸（TPA）和六氯环三磷腈（HCCP）为原料，通过缩聚反应制备了TPA-HCCP COF。制备的COF阳极具有稳定的微孔结构和丰富的活性位点，具有0.26 V的低放电电位、120 mA h g−1的高可逆比容量和良好的倍率性能。由于CO的电活性位点和N的配位位点对钠离子的作用，COF的钠离子储存动力学是一个扩散和电容的结合过程。以Na4Fe3(PO4)2(P2O7) （NFPP）为正极材料制备了全电池，以评价COF阳极在宽工作温度下的实际应用潜力。NFPP||COF电池具有3.0 V的高平均电压和118 mA h g−1的比放电容量。本研究为设计和制备对苯二甲酸盐基COF负极材料提供了一种有效的策略，并验证了其在sib中的实际应用潜力。

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引用次数: 0

Investigation of the luminescent properties of a narrow-band blue-emitting phosphor BaAl12O19: Eu2+/EuAl12O19 for WLED backlight displays WLED背光显示用窄带蓝光荧光粉BaAl12O19: Eu2+/EuAl12O19发光特性研究

IF 3.5 3区化学 Q2 CHEMISTRY, INORGANIC & NUCLEAR

Journal of Solid State Chemistry

Pub Date : 2025-12-03 DOI: 10.1016/j.jssc.2025.125759

Qingyun Yan, Zhongxiang Shi, Yingnan Dong, Jing Wang

Motivated by the need to exhance the versatility of rare-earth-doped phosphors for solid-state lighting, a series of Eu²⁺-doped BaAl₁₂O₁₉ (BAO: Eu) materials exhibiting narrow-band blue emission were synthesized via a high-temperature solid-state reaction. X-ray diffraction analysis confirmed that the synthesized phosphors crystallize in a pure hexagonal BaAl₁₂O₁₉ phase. Microscopic analysis revealed that the powder consists of uniformly sized microparticles with a hexagonal prism morphology. The BAO: Eu²⁺ phosphors exhibit strong absorption in the 325–410 nm, making them suitable for excitation by near-ultraviolet (NUV) LED chips. Upon excitation at 365 nm, these phosphors emit a narrow-band blue light centered at 445 nm. The emission intensity increases with Eu²⁺ ratio until a quenching threshold is reached at x > 0.28. Notably, the highly symmetric crystal structure of the BaAl₁₂O₁₉ host lattice imparts remarkable luminous thermal stability to the BAO: xEu²⁺ phosphors. Over the temperature range of 298–498 K, the emission intensity at 150 °C retains 91.1 % of its initial value at room temperature. Furthermore, this series of phosphors exhibits high color purity, reaching an optimal value of 99.69 % at a doping ratio of x = 0.28. To demonstrate a practical application beyond lighting, an advanced anti-counterfeiting ink was formulated by dispersing the phosphors into commercial ink. This ink produces a sharp imaging effect under UV light, enabling rapid information decryption and significantly enhancing anti-counterfeiting security. Finally, a prototype blue LED device was fabricated by combining the Ba₀_·₇₂Al₁₂O₁₉: 0.28Eu²⁺ phosphor with a 365 nm near-UV chip. The device demonstrates a high color rendering index, excellent color consistency, and superior color reproduction, underscoring its significant potential in solid-state lighting applications. In conclusion, the BAO: xEu²⁺ phosphors, characterized by their narrow-band emission, exceptional luminous thermal stability, and high color purity, represent a highly promising blue-emitting material for near-UV-pumped white LEDs.

为了提高稀土掺杂荧光粉在固态照明中的通用性，通过高温固态反应合成了一系列具有窄带蓝光发射的Eu2+掺杂BaAl12O19 （BAO: Eu）材料。x射线衍射分析证实，合成的荧光粉结晶为纯六方BaAl12O19相。显微分析表明，粉末由均匀大小的微粒组成，具有六棱柱状形貌。BAO: Eu2+荧光粉在325-410 nm范围内具有很强的吸收，适合近紫外（NUV） LED芯片激发。在365 nm的激发下，这些荧光粉发出以445 nm为中心的窄带蓝光。发射强度随Eu2+比的增加而增加，直至达到淬灭阈值x >； 0.28。值得注意的是，BaAl12O19主体晶格的高度对称晶体结构赋予BAO: xEu2+荧光粉显著的发光热稳定性。在298 ~ 498 K的温度范围内，150℃时的发射强度保持在室温初始值的91.1%。此外，该系列荧光粉具有较高的色纯度，在掺杂比x = 0.28时达到99.69%的最佳值。为了演示照明以外的实际应用，将荧光粉分散到商业油墨中配制了一种先进的防伪油墨。该油墨在紫外光下可产生清晰的成像效果，使信息快速解密，显著增强防伪安全性。最后，将Ba0·72Al12O19: 0.28Eu2+荧光粉与365 nm近紫外芯片相结合，制备了蓝色LED原型器件。该器件具有高显色指数、出色的色彩一致性和卓越的色彩再现性，强调了其在固态照明应用中的巨大潜力。总之，BAO: xEu2+荧光粉具有窄带发光、优异的发光热稳定性和高色纯度等特点，是一种非常有前途的近紫外泵浦白光led蓝色发光材料。

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引用次数: 0

Synergistic strategy and mechanistic elucidation of efficient Cr(VI) photoreduction by heterojunction BiOI/B-g-C3N4 hybrids 异质结BiOI/B-g-C3N4杂化物高效光还原Cr（VI）的协同策略及机理研究

IF 3.5 3区化学 Q2 CHEMISTRY, INORGANIC & NUCLEAR

Journal of Solid State Chemistry

Pub Date : 2025-11-29 DOI: 10.1016/j.jssc.2025.125758

Wangchao Su , Yuhang Gao , Lijun Nie , Yueyu Ma , Xiaobei Han , Lirong Ren , Jianhui Shi

Bismuth iodide oxide/boron-doped graphitic carbon nitride (BiOI/BCN) with a type II heterojunction structure was rationally designed and controllably synthesized using calcination and hydrothermal methods. The loading of BCN can be adjusted to effectively regulate both the electronic band structure and photocatalytic performance of the BiOI/BCN heterojunction. Under simulated sunlight irradiation and without adding an additional sacrificial agent, the BiOI/BCN-1 composite with the optimal doping ratio demonstrated exceptional photocatalytic performance. It completely reduced Cr(VI) within 40 min, with a reaction rate constant of 0.1283 min⁻¹, which was 5.7 times that of pristine BCN and 1.27 times that of BiOI. The superior photocatalytic performance of BiOI/BCN-1 is attributed to its enhanced visible-light absorption, larger specific surface area, increased active sites, and efficient separation of photogenerated carriers, all of which are facilitated by the Type II heterojunction. Recycling tests confirmed that BiOI/BCN-1 maintains high activity even after five cycles. Furthermore, radical trapping experiments confirmed that

e^{-}

and

\cdot O_{2}^{-}

are the dominant active species responsible for the photocatalytic reduction of Cr(VI). This study establishes a strategic method for designing and synthesizing highly efficient Type II heterojunction photocatalysts, providing an effective approach for the photocatalytic reduction of heavy metal ions in wastewater.

采用煅烧法和水热法制备了具有II型异质结结构的碘化铋氧化物/掺硼石墨氮化碳（BiOI/BCN）。BCN的负载可以调节，从而有效地调节BiOI/BCN异质结的电子能带结构和光催化性能。在模拟阳光照射下，在不添加额外牺牲剂的情况下，具有最佳掺杂比的BiOI/BCN-1复合材料表现出优异的光催化性能。在40 min内完全还原Cr(VI)，反应速率常数为0.1283 min−1，是原始BCN的5.7倍，BiOI的1.27倍。BiOI/BCN-1优越的光催化性能是由于其可见光吸收增强，比表面积更大，活性位点增加，光生载流子的有效分离，这些都是II型异质结促进的。回收试验证实，即使在五个循环后，BiOI/BCN-1仍保持高活性。此外，自由基捕获实验证实，e−和·O2−是光催化还原Cr（VI）的主要活性物质。本研究建立了设计和合成高效II型异质结光催化剂的策略方法，为光催化还原废水中重金属离子提供了有效途径。

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引用次数: 0

Strong oxidizing annealing of bilayer La3Ni2O7-δ results in suppression of superconductivity under high pressure 双层La3Ni2O7-δ的强氧化退火抑制了高压下的超导性

IF 3.5 3区化学 Q2 CHEMISTRY, INORGANIC & NUCLEAR

Journal of Solid State Chemistry

Pub Date : 2025-11-29 DOI: 10.1016/j.jssc.2025.125757

Yulin Zhang , Cuiying Pei , Ning Guo , Feiyu Li , Longlong Fan , Mingxin Zhang , Lingzhen Wang , Gongting Zhang , Yunong Wang , Chao Ma , Wenyong Cheng , Shanpeng Wang , Qiang Zheng , Yanpeng Qi , Junjie Zhang

The discovery of superconductivity with an onset temperature of ∼80 K in pressurized bilayer Ruddlesden-Popper La₃Ni₂O_7-δ has attracted much attention. Despite intense research, determination of the exact oxygen content and understanding of the relationship between superconductivity and oxygen content remain a big challenge. Here, we report a systematical study on the structure and physical properties of La₃Ni₂O_7-δ polycrystalline powders which were prepared using the sol-gel method at ambient pressure and then annealed under high oxygen pressure (pO₂) or in ozone. The superconducting transition of La₃Ni₂O_7-δ at ∼80 K under high pressure is suppressed for high pO₂ and ozone annealed samples. We attribute this to the combination of the following two reasons: (i) damage of the bilayer structure, as revealed by powder X-ray diffraction, scanning transmission electron microscopy and pair distribution function measurements, and (ii) hole overdoping due to the increasing of oxygen content. Our results reveal that the bilayer structure in La₃Ni₂O_7-δ is fragile and post-annealing under mild oxidization is suitable for maintaining the integrity of the bilayer structure and increasing oxygen content.

Ruddlesden-Popper双层La3Ni2O7-δ的超导性的发现引起了人们的广泛关注。尽管进行了大量的研究，但确定确切的氧含量以及了解超导性和氧含量之间的关系仍然是一个巨大的挑战。本文系统地研究了用溶胶-凝胶法制备La3Ni2O7-δ多晶粉末的结构和物理性能，并对其进行了高氧（pO2）或臭氧退火。高pO2和臭氧退火样品在~ 80k高压下La3Ni2O7-δ的超导转变被抑制。我们认为这是由于以下两个原因的结合：(i)通过粉末x射线衍射、扫描透射电子显微镜和对分布函数测量显示的双层结构的破坏；（ii）由于氧含量的增加而导致的空穴过度掺杂。结果表明，La3Ni2O7-δ的双层结构是脆弱的，轻度氧化后退火有利于保持双层结构的完整性和提高氧含量。

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引用次数: 0

Experimental and theoretical evidence of nodal line semimetallic state in SmSbSe SmSbSe中节线半金属态的实验和理论证据

IF 3.5 3区化学 Q2 CHEMISTRY, INORGANIC & NUCLEAR

Journal of Solid State Chemistry

Pub Date : 2025-11-28 DOI: 10.1016/j.jssc.2025.125740

Aarti Gautam , Haribrahma Singh , Pabitra Kumar Nayak , Prabuddha Kant Mishra , Rie Y. Umetsu , Dibyajyoti Ghosh , Ashok Kumar Ganguli

We report a detailed investigation of the magnetic, transport, magneto-transport, and thermodynamic properties of the synthesized compound SmSbSe, a new member of the ZrSiS-type topological material family. Magnetic susceptibility measurements reveal an antiferromagnetic (AFM) ground state below T

_{N} =

3.2 K, corroborated by a pronounced

λ

-shaped anomaly in the specific heat. Deviation from Curie–Weiss behavior indicates mixing of the ground state with an excited state multiplet above 1001 K, further supported by

C_{p}

(T) data, where crystalline electric field (CEF) effects are manifested as a splitting of the ground state into a low-lying doublet and a higher excited level. Isothermal magnetization curves exhibit signatures of field-induced metamagnetic transition. Electrical resistivity measurements showed a nonmetallic temperature dependence with a noticeable change in slope near the Néel temperature, suggesting strong coupling between magnetic and transport properties. Remarkably, SmSbSe exhibits a large, non-saturating magnetoresistance

\approx

(55% at 2 K) with a significant crossover from quadratic to linear field dependence, indicative of Dirac-like band dispersion. Further, the deviation from Kohler’s scaling along with nonlinearity in Hall resistivity data indicates the presence of multiple charge carriers. The electronic band structure calculations confirm the presence of Dirac nodal-line semimetallic state in SmSbSe.

我们报告了对合成的化合物SmSbSe的磁性、输运、磁输运和热力学性质的详细研究，SmSbSe是zrsis型拓扑材料家族的新成员。磁化率测量显示，在TN= 3.2 K以下存在反铁磁基态（AFM），并在比热中出现明显的λ形异常。偏离居里-魏斯行为表明基态与激发态倍数在1001 K以上混合，这进一步得到了Cp(T)数据的支持，其中晶体电场（CEF）效应表现为基态分裂为低处的双重态和较高的激发态。等温磁化曲线表现出场致变磁跃迁特征。电阻率测量显示非金属温度依赖与nsamel温度附近斜率的显著变化，表明磁性和输运性质之间存在强耦合。值得注意的是，SmSbSe表现出较大的非饱和磁电阻≈(2 K时为55%)，并具有从二次场依赖到线性场依赖的显著交叉，表明了狄拉克类能带色散。此外，霍尔电阻率数据与科勒标度的偏差以及非线性表明存在多个载流子。电子能带结构计算证实了SmSbSe中存在Dirac节线半金属态。

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引用次数: 0

Stability studies of barium tungstates: A combined thermogravimetric and X-ray diffraction investigation 钨酸钡的稳定性研究：结合热重法和x射线衍射法的研究

IF 3.5 3区化学 Q2 CHEMISTRY, INORGANIC & NUCLEAR

Journal of Solid State Chemistry

Pub Date : 2025-11-28 DOI: 10.1016/j.jssc.2025.125755

Geeta Patkare , Muhammed Shafeeq , Rohan Phatak , Bal Govind Vats , Meera Keskar

Structural and thermal properties of ternary barium tungstates were investigated using powder X-ray diffraction (XRD) and thermogravimetric (TG) techniques. BaWO₄, Ba₃W₂O₉, Ba₂WO₅ and Ba₃WO₆ compounds were synthesized using solid state route. BaWO₄ is stable in air whereas other tungstates are unstable when stored under normal atmospheric conditions. XRD and TG analysis of the stored samples confirmed that except BaWO₄ all other tungstates decompose to a mixture of BaWO₄ and BaO. The decomposed BaO readily converts into BaCO₃ and never observed as BaO in the decomposed product. Decomposition of these tungstates is a function of storage time at ambient condition and barium content in the compounds. Almost complete decomposition was observed in case of Ba₃WO₆ and Ba₂WO₅ when stored for 160 days at ambient conditions. The fraction (mole%) of decomposed products i.e. BaWO₄ and BaCO₃ (in turn BaO) in Ba₂WO₅ and Ba₃WO₆ were calculated from Rietveld refinement of XRD patterns which ascertains that Ba₃WO₆ decomposes faster than Ba₂WO₅. Thermal expansion coefficients of all freshly synthesized tungstates were calculated from high temperature XRD data from ambient to 1273 K in argon atmosphere. All the synthesized tungstates showed positive expansion in the range of 30–44 × 10⁻⁶ K⁻¹ without any degradation under inert atmosphere. This study clearly shows that on storage under ambient conditions, stability of multiple stoichiometric compounds in alkaline earth tungstate has to be ascertained before the proposed applications.

采用粉末x射线衍射（XRD）和热重（TG）技术研究了三元钨酸钡的结构和热性能。采用固态法合成了BaWO4、Ba3W2O9、Ba2WO5和Ba3WO6化合物。BaWO4在空气中是稳定的，而其他钨酸盐在正常大气条件下储存时是不稳定的。存储样品的XRD和TG分析证实，除BaWO4外，其余钨酸盐均分解为BaWO4和BaO的混合物。分解后的BaO很容易转化为BaCO3，在分解产物中从未观察到BaO。这些钨酸盐的分解是在环境条件下储存时间和化合物中钡含量的函数。Ba3WO6和Ba2WO5在常温条件下保存160天，几乎完全分解。通过XRD谱图的Rietveld细化计算了Ba2WO5和Ba3WO6中分解产物BaWO4和BaCO3（依次为BaO）的摩尔分数（mol %），确定Ba3WO6的分解速度比Ba2WO5快。利用室温至1273 K氩气氛下的高温XRD数据计算了所有新合成的钨酸盐的热膨胀系数。在惰性气氛下，所有合成的钨酸盐在30-44 × 10−6 K−1范围内均呈正膨胀，未发生降解。这项研究清楚地表明，在环境条件下储存时，在提出应用之前，必须确定多种化学计量化合物在碱土钨酸盐中的稳定性。

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引用次数: 0

Neutron diffraction study of ScFe2Dx compounds ScFe2Dx化合物的中子衍射研究

IF 3.5 3区化学 Q2 CHEMISTRY, INORGANIC & NUCLEAR

Journal of Solid State Chemistry

Pub Date : 2025-11-26 DOI: 10.1016/j.jssc.2025.125754

S. El Bidaoui , L.V.B. Diop , O. Isnard

The crystal and magnetic structures of ScFe₂ and its deuteride ScFe₂D_3.2 have been investigated by neutron powder diffraction. The C14 hexagonal MgZn₂-type crystal structure of the initial alloy ScFe₂ is maintained upon the insertion of 3.2 D/f.u. Deuterium localization within the crystal lattice reveals occupancy of four tetrahedral interstitial sites, each coordinated by two Sc and two Fe atoms. Among these, the 6h₂ and 12k₁ sites are filled at 77 % and 27 % respectively, while the 24l and 6h₁ are less than 20 % occupy. The magnetic moment magnitudes have been determined for the two inequivalent Fe sites (2a and 6h) using Rietveld analysis of the magnetic structure; both increase with deuterium insertion. It is found that the magnetic moment orientation at low temperature changes upon deuterium absorption. For ScFe₂, the Fe magnetic moments are aligned at an angle of 30° with respect of the c-axis, whereas for ScFe₂D_3.2 they lie within the basal plane of the hexagonal structure. We also report the thermal evolution of the lattice parameters for both compounds over the temperature range of 2 K–300 K. ScFe₂ exhibits typical thermal expansion behavior bellow 300 K, while ScFe₂D_3.2 displays unusual lattice parameters variations with temperature.

用中子粉末衍射法研究了ScFe2及其氘化物ScFe2D3.2的晶体结构和磁性结构。当加入3.2 D/f.u时，初始合金ScFe2仍保持C14六方mgzn2型晶体结构。氘在晶格内的定位表明占据了四个四面体间隙位，每个空位由两个Sc和两个Fe原子配位。其中6h2和12k1位点的填充率分别为77%和27%，而24l和6h1的填充率不到20%。利用磁性结构的Rietveld分析确定了两个不相等的Fe位点（2a和6h）的磁矩大小；两者都随着氘的加入而增加。发现在低温下磁矩取向随着氘的吸收而发生变化。对于ScFe2， Fe磁矩与c轴呈30°角排列，而对于ScFe2D3.2，它们位于六边形结构的基面上。我们还报道了两种化合物的晶格参数在2 K - 300 K温度范围内的热演化。ScFe2在300 K以下表现出典型的热膨胀行为，而ScFe2D3.2晶格参数随温度变化不寻常。

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引用次数: 0