Physica B-condensed Matter最新文献

英文中文

Magnetic structure and colossal dielectric properties in Ga3+ substituted Zn2Y hexaferrites by chemical co-precipitation method 化学共沉淀法制备的 Ga3+ 取代 Zn2Y 六铁氧体的磁结构和巨大介电性能

IF 2.8 3区物理与天体物理 Q2 PHYSICS, CONDENSED MATTER

Physica B-condensed Matter

Pub Date : 2024-10-16 DOI: 10.1016/j.physb.2024.416635

Y-type Ba_0.5Sr_1.5Zn₂Fe_12-xGa_xO₂₂ (x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) hexaferrites are prepared through modified chemical co-precipitation method. X-ray diffraction (XRD) results reveal that these samples are single-phase and the space group is

R \overline{3} m

. The field-emission scanning electronic microscope (FE-SEM) measurements indicate that the grains are hexagonal-plate with a diameter of 2–5 μm. In the M-T diagrams, various magnetic structures are modulated, including proper-screw, longitudinal conical (LC), mixed conical (MC), and collinear ferrimagnetic (collinear FIM). In this series of samples, the values of dielectric constant (

ε^{'}

) achieve an order increase from 10² to 10⁴. For the best x = 0.8 sample, the

ε^{'}

is as high as 1804.76 at 1 MHz and 300 K. In conclusion, Ba_0.5Sr_1.5Zn₂Fe_12-xGa_xO₂₂ with controllable magnetic structures and colossal dielectric constant are potential materials for miniaturization of modern electronic devices.

通过改良化学共沉淀法制备了 Y 型 Ba0.5Sr1.5Zn2Fe12-xGaxO22（x = 0.0、0.2、0.4、0.6、0.8 和 1.0）六铁氧体。X 射线衍射（XRD）结果表明，这些样品为单相，空间群为 R3-‾m。场发射扫描电子显微镜（FE-SEM）测量结果表明，晶粒呈六角板状，直径为 2-5 μm。在 M-T 图中，出现了各种磁性结构，包括正螺旋、纵锥形（LC）、混合锥形（MC）和准铁磁（Collinear FIM）。在这一系列样品中，介电常数 (ε′) 的值实现了从 102 到 104 的数量级增长。总之，具有可控磁性结构和巨大介电常数的 Ba0.5Sr1.5Zn2Fe12-xGaxO22 是现代电子设备微型化的潜在材料。

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引用次数: 0

Investigation of magneto-optoelectronics properties of Mg1-xMnxS alloys for optoelectronics and spintronic applications 用于光电子学和自旋电子学应用的 Mg1-xMnxS 合金的磁光特性研究

IF 2.8 3区物理与天体物理 Q2 PHYSICS, CONDENSED MATTER

Physica B-condensed Matter

Pub Date : 2024-10-15 DOI: 10.1016/j.physb.2024.416629

Herein, the optical, electronic and magnetic properties of Mg_1-xMn_xS alloys are computed by employing density functional theory. The full-potential linearized augmented plane wave (FP-LAPW) method was used within the frame work of Wein2k to explore spin polarized band structure along with total and partial density of states. The results of spin polarized band structure calculations exhibited semiconducting character in both spin states. The net magnetic moment (μ_B) is primarily credited to presence of partially filled 3d state of Mn atom. μ_B gives evidence of p-d hybridization between orbitals of Mn and parent lattice ions. Optical characteristics of Mg_1-xMn_xS including dielectric constants along with relevant features have been reported at 0–10 eV energy range. High value of absorption coefficient and smaller reflectance in ultraviolet energy span suggests potentiality of doped alloy for optoelectronic applications. Moreover, ferromagnetic character makes it suitable for spintronic storage devices.

本文采用密度泛函理论计算了 Mg1-xMnxS 合金的光学、电子和磁学特性。在 Wein2k 的框架内使用了全电位线性化增强平面波（FP-LAPW）方法来探索自旋极化带结构以及总态密度和部分态密度。自旋极化带结构计算的结果表明，两种自旋态都具有半导体特性。净磁矩（μB）主要归功于锰原子部分填充 3d 态的存在。据报道，Mg1-xMnxS 的光学特性包括介电常数以及 0-10 eV 能量范围内的相关特征。紫外线能量范围内的高吸收系数和较小的反射率表明，掺杂合金具有光电应用的潜力。此外，铁磁特性也使其适用于自旋电子存储设备。

引用次数: 0

Persistence luminescence and thermoluminescence of 260 nm UVC irradiated mixed-phase (BaAl2O4 - BaAl12O19) barium aluminate 经 260 纳米紫外线照射的混相（BaAl2O4 - BaAl12O19）铝酸钡的持久发光和热致发光

IF 2.8 3区物理与天体物理 Q2 PHYSICS, CONDENSED MATTER

Physica B-condensed Matter

Pub Date : 2024-10-13 DOI: 10.1016/j.physb.2024.416628

Persistence luminescence (PerL) and thermoluminescence (TL) of BaAl₂O₄ - BaAl₁₂O₁₉ mixedphase compound under 260 nm UVC irradiation are studied. The sample shows PerL for more than 1 h post irradiation. TL glow curves of the sample recorded at 1 ^oC/s following irradiation to UVC radiation shows a composite glow peak between 30 and 230 °C. The TL intensity is found to be affected by thermal quenching. The activation energy for thermal quenching is estimated to be W = 0.85 ± 0.12 eV. A T_m-T_stop analysis reveals that the TL glow peak is composed of multiple first order components. The activation energy associated with the electron traps are found to vary from 0.66 to 1.70 eV. The density of the traps is high between 0.60 and 1.20 eV. Due to presence of continuous distribution of electron traps, there is an excellent scope of developing colour tuneable persistence luminescence phosphor using mixed phase barium aluminate.

研究了在 260 纳米紫外线照射下 BaAl2O4 - BaAl12O19 混相化合物的持续发光（PerL）和热发光（TL）。样品在辐照后 1 小时以上都显示 PerL。样品在接受紫外线照射后以 1 oC/s 的速度记录的 TL 辉光曲线显示出 30 至 230 °C 之间的复合辉光峰。热淬火会影响 TL 强度。热淬火的活化能估计为 W = 0.85 ± 0.12 eV。Tm-Tstop 分析显示，TL 辉光峰由多个一阶成分组成。发现与电子陷阱相关的活化能在 0.66 至 1.70 eV 之间变化。陷阱密度在 0.60 至 1.20 eV 之间较高。由于存在连续分布的电子陷阱，使用混合相铝酸钡开发颜色可调的持久发光荧光粉具有广阔的前景。

引用次数: 0

Synthesis, characterization, electrochemical impedance spectroscopy performance and photodegradation of methylene blue: Mesoporous PEG/TiO2 by sol-gel electrospinning 亚甲基蓝的合成、表征、电化学阻抗谱性能和光降解：溶胶-凝胶电纺丝法制备介孔 PEG/TiO2

IF 2.8 3区物理与天体物理 Q2 PHYSICS, CONDENSED MATTER

Physica B-condensed Matter

Pub Date : 2024-10-13 DOI: 10.1016/j.physb.2024.416627

Sol-gel and electrospinning methods successfully prepared porous TiO₂ fibers. The samples were calcined at temperatures of 450 °C and 550 °C and characterized using different techniques. XRD analysis also revealed crystalline anatase and rutile phases of mp-TiO₂ observed at calcining temperatures of 450 °C and 550 °C, whereas as-prepared showed an amorphous-like structure. Relatively higher surface area and photocatalytic efficiency were increased with a decrease in crystallite size. All samples absorb UV region. The Rs value of TiO₂ calcined at 550 °C was 16.6 Ω, which is much lower than those of the 450 °C calcined TiO₂ powder electrode (52.7 Ω) and as-prepared TiO₂ electrode (95.3 Ω). In addition, the Rp resistance of TiO₂ calcined at 550 °C electrode (5.85 kΩ) was also lower than those of 450 °C calcined TiO₂ powder (39.0 kΩ) and as-prepared TiO₂ electrode (68.9 kΩ), revealing better electronic and ionic conduction of TiO₂ calcined at 550 °C electrode.

溶胶凝胶法和电纺丝法成功制备了多孔二氧化钛纤维。样品在 450 ℃ 和 550 ℃ 的温度下煅烧，并采用不同的技术进行表征。XRD 分析还显示，在 450 ℃ 和 550 ℃ 的煅烧温度下，mp-TiO2 可观察到锐钛矿相和金红石相结晶，而制备的样品则显示出无定形结构。随着晶体尺寸的减小，比表面积和光催化效率也相对增大。所有样品都能吸收紫外线。550 °C 煅烧的 TiO2 的 Rs 值为 16.6 Ω，远低于 450 °C 煅烧的 TiO2 粉末电极（52.7 Ω）和未制备的 TiO2 电极（95.3 Ω）。此外，550 ℃煅烧的二氧化钛电极的 Rp 电阻（5.85 kΩ）也低于 450 ℃煅烧的二氧化钛粉末电极（39.0 kΩ）和制备的二氧化钛电极（68.9 kΩ），这表明 550 ℃煅烧的二氧化钛电极具有更好的电子和离子传导性。

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引用次数: 0

Structural, morphological and optical properties of the La2W2O9/Fe2O3 composite for UV-shielding applications 用于紫外线屏蔽应用的 La2W2O9/Fe2O3 复合材料的结构、形态和光学特性

IF 2.8 3区物理与天体物理 Q2 PHYSICS, CONDENSED MATTER

Physica B-condensed Matter

Pub Date : 2024-10-12 DOI: 10.1016/j.physb.2024.416618

Currently, research has been conducted on the individual oxides La₂W₂O₉ and Fe₂O₃ but not on its composite form. Using a solid-state reaction technique, a La₂W₂O₉/Fe₂O₃ composite was created. A particular calcination cycle was followed by mixing the raw precursors. Scanning electron microscopy (SEM) was used to investigate the morphological microstructure, and X-ray diffraction (XRD) was used to examine the structural characteristics. The thermal and gravimetric properties were examined via differential thermal analysis (DTA) and thermogravimetric analysis (TGA). The optical characteristics were investigated via UV–visible spectroscopy, which investigated included the transmittance, absorbance, absorption coefficient, band gap (E_g), penetration depth (β), Urbach energy (E_U), refractive index, optical conductivity, and dielectric function. These findings indicate that the optical properties improved after the addition of Fe₂O₃ compared with those of pure La₂W₂O₉. The La₂W₂O₉/Fe₂O₃ composite holds promise as a prospective material for use in the fields of sunscreen products, UV shielding or solar filtration.

目前，人们已经对单个氧化物 La2W2O9 和 Fe2O3 进行了研究，但尚未对其复合形式进行研究。利用固态反应技术，我们制造出了 La2W2O9/Fe2O3 复合材料。在特定的煅烧循环中，混合了原材料前驱体。扫描电子显微镜（SEM）用于研究形态微观结构，X 射线衍射（XRD）用于研究结构特征。通过差热分析（DTA）和热重分析（TGA）研究了热和重力特性。通过紫外-可见光谱分析了光学特性，包括透射率、吸光度、吸收系数、带隙（Eg）、穿透深度（β）、厄巴赫能（EU）、折射率、光导率和介电函数。这些研究结果表明，与纯 La2W2O9 相比，加入 Fe2O3 后光学特性得到改善。La2W2O9/Fe2O3 复合材料有望在防晒产品、紫外线屏蔽或太阳能过滤等领域得到应用。

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引用次数: 0

Photoluminescence properties of SnO2 nanoparticles doped with group VI elements (Cr, Mo, W) synthesized by pulsed laser ablation in liquid 在液体中通过脉冲激光烧蚀合成的掺杂 VI 族元素（铬、钼、钨）的 SnO2 纳米粒子的光致发光特性

IF 2.8 3区物理与天体物理 Q2 PHYSICS, CONDENSED MATTER

Physica B-condensed Matter

Pub Date : 2024-10-12 DOI: 10.1016/j.physb.2024.416625

Tin oxide nanoparticles (SnO₂ NPs), both pure and doped with Group VI (G6) metal ions (Cr⁺³, Mo⁺⁵, and W⁺⁶), were synthesized using pulsed laser ablation in liquid. This study aimed to investigate the effect of G6 doping on the electronic properties of SnO₂ NPs, with an emphasis on enhancing their photoluminescence for optoelectronic applications. Transmission electron microscopy revealed well-crystallized samples with diameters of 3–6 nm, indicating quantum-confinement effects. The optical band gap, determined by UV–Vis spectroscopy, was reduced from 5.1 eV (undoped) to 4.9 eV (Cr-doped) due to defect states, while increasing to 5.3 eV and 5.7 eV for Mo- and W-doped SnO₂, respectively, due to the Moss-Burstein effect. The photoluminescence spectra exhibited a redshift, with strong red emission around 700 nm, which was up to 90 % more intense than that of the undoped SnO₂. This enhancement was attributed to the ²E→⁴A₂ transition and increased defect states.

本研究利用脉冲激光烧蚀技术在液体中合成了纯氧化锡纳米粒子（SnO2 NPs）和掺杂第六族（G6）金属离子（Cr+3、Mo+5 和 W+6）的氧化锡纳米粒子（SnO2 NPs）。本研究旨在探讨 G6 掺杂对 SnO2 NPs 电子特性的影响，重点是增强其在光电应用中的光致发光性能。透射电子显微镜显示了直径为 3-6 纳米的良好结晶样品，表明其具有量子会聚效应。通过紫外可见光谱测定，由于缺陷态，光带隙从 5.1 eV（未掺杂）减小到 4.9 eV（掺杂铬），而由于莫斯-伯斯坦效应，掺 Mo 和 W 的 SnO2 的光带隙分别增大到 5.3 eV 和 5.7 eV。光致发光光谱表现出红移，在 700 纳米附近有强烈的红色发射，其强度比未掺杂 SnO2 高出 90%。这种增强归因于 2E→4A2 转变和缺陷态的增加。

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引用次数: 0

Gradient distribution of cations in rhabdophane La0.27Y0.73PO4·nH2O nanoparticles 阳离子在La0.27Y0.73PO4-nH2O纳米颗粒中的梯度分布

IF 2.8 3区物理与天体物理 Q2 PHYSICS, CONDENSED MATTER

Physica B-condensed Matter

Pub Date : 2024-10-12 DOI: 10.1016/j.physb.2024.416623

The structure of gradient rhabdophane nanoparticles of variable composition (La,Y)PO₄·nH₂O obtained by precipitation is considered. According to the data of HAADF TEM and EDX mapping using the Abel inversion procedure, it was shown that there is an inhomogeneous distribution of yttrium and lanthanum atoms in the particles from the central part to the periphery. At the same time, the nominal composition of both individual nanoparticles and the entire sample meets the value specified during synthesis within the error of the method – La_0.27Y_0.73PO₄·nH₂O. According to SAXS data, it was determined that in the particles of (La,Y)PO₄·nH₂O, there is a redistribution of scattering densities, which is caused by an increase in the fraction of YPO₄ in the peripheral region of the particles. The observed effect of the distribution of cations over the particle made it possible to determine the size of the gradient layer, which reaches 50 % of the total particle size.

研究了通过沉淀法获得的不同成分（La,Y）PO4-nH2O 的梯度菱形纳米粒子的结构。根据使用阿贝尔反演程序绘制的 HAADF TEM 和 EDX 图谱数据，可以看出颗粒中的钇原子和镧原子从中心到外围分布不均匀。同时，单个纳米粒子和整个样品的标称成分都符合合成时规定的值--La0.27Y0.73PO4-nH2O，误差在方法误差范围内。根据 SAXS 数据确定，(La,Y)PO4-nH2O 颗粒中的散射密度存在重新分布，这是由于颗粒外围区域的 YPO4 分数增加造成的。根据观察到的阳离子在颗粒上分布的影响，可以确定梯度层的大小，该梯度层达到总粒度的 50%。

引用次数: 0

Investigation of rare earth metal ions (Sm and Er) doped CoMoO4 polymorphs for photocatalytic dye degradation 掺杂稀土金属离子（Sm 和 Er）的 CoMoO4 多晶体光催化染料降解研究

IF 2.8 3区物理与天体物理 Q2 PHYSICS, CONDENSED MATTER

Physica B-condensed Matter

Pub Date : 2024-10-11 DOI: 10.1016/j.physb.2024.416616

Cobalt molybdate (CoMoO₄) and its rare earth doped variants have emerged as promising photocatalysts for degrading dye pollutants in wastewater. The photocatalysts were prepared using a modified sol-gel method, employing ammonium heptamolybdate tetrahydrate and cobalt (II) nitrate hexahydrate as precursors. The incorporation of samarium and erbium as a dopant was hypothesized to improve the photocatalytic activity of CoMoO₄ by altering its band structure and creating defect sites for improved dye adsorption and degradation. The structural and optical properties of the synthesized photocatalysts were characterized using various techniques. The photocatalytic performance of CoMoO₄, Sm:CoMoO₄ and Er:CoMoO₄ was evaluated by monitoring the degradation of MB dye under light irradiation. The results reveal that Sm:CoMoO₄ and Er:CoMoO₄ catalysts achieve a degradation efficiencies of 99 % and 97 %, respectively, highlighting the potential of rare earth-doped CoMoO₄ as an efficient photocatalyst for the remediation of dye contaminated wastewater.

钼酸钴（CoMoO4）及其掺杂稀土的变体已成为降解废水中染料污染物的有前途的光催化剂。这些光催化剂采用改良的溶胶-凝胶法，以四水七钼酸铵和六水硝酸钴 (II) 为前驱体进行制备。掺入钐和铒作为掺杂剂，可以改变 CoMoO4 的能带结构，产生缺陷位点，从而改善染料的吸附和降解，从而提高其光催化活性。利用各种技术对合成光催化剂的结构和光学特性进行了表征。通过监测光照射下 MB 染料的降解情况，评估了 CoMoO4、Sm:CoMoO4 和 Er:CoMoO4 的光催化性能。结果表明，Sm:CoMoO4 和 Er:CoMoO4 催化剂的降解效率分别达到 99% 和 97%，凸显了稀土掺杂 CoMoO4 作为高效光催化剂修复染料污染废水的潜力。

引用次数: 0

Anisotropic magnetic entropy change and magnetic critical behavior in van der Waals Fe3GaTe2 范德华Fe3GaTe2中各向异性的磁熵变化和磁临界行为

IF 2.8 3区物理与天体物理 Q2 PHYSICS, CONDENSED MATTER

Physica B-condensed Matter

Pub Date : 2024-10-11 DOI: 10.1016/j.physb.2024.416615

Fe₃GaTe₂, with intrinsic magnetism at ambient temperature and high perpendicular magnetic anisotropy, is a promising van der Waals material for 2D-materials-based spintronic devices. Herein, we report the anisotropic magnetocaloric effects and magnetic critical phenomena in Fe₃GaTe₂ single crystal. Owing to the large anisotropy, magnetic entropy change

(- Δ S_{M})

shows anisotropic character with

- Δ S_{M}^{\max}

of 1.67 J kg⁻¹ K⁻¹ along the c axis and 1.11 J kg⁻¹ K⁻¹ in the ab plane under field change of 5 T. The rotating

Δ S_{M}

from the ab plane to the c axis reaches 0.67 J kg⁻¹ K⁻¹ at magnetic field of 5 T. By carefully fitting the

- Δ S_{M}^{\max}

and relative cooling power (RCP), we determine their relationships to be

- Δ S_{M}^{\max} \propto H^{n}

(n = 0.694(1)) and

R C P \propto H^{m}

(m = 1.301(3)) for the magnetic field along the c-axis. Further analysis of critical behavior near T_C reveals critical exponents β = 0.41(1) at T_C = 341.5(1) K, γ = 1.01(1) at T_C = 341.6(3) K, and δ = 3.67(15) at T_C = 340 K, indicating a three-dimensional complex magnetic exchange.

Fe3GaTe2 在常温下具有本征磁性和高垂直磁各向异性，是一种很有前途的范德华材料，可用于基于二维材料的自旋电子器件。在此，我们报告了 Fe3GaTe2 单晶的各向异性磁致效应和磁临界现象。由于存在较大的各向异性，磁熵变化（-ΔSM）呈现出各向异性的特征，在磁场变化为 5 T 时，沿 c 轴的-ΔSM 最大值为 1.67 J kg-1 K-1，在 ab 平面上为 1.11 J kg-1 K-1。通过仔细拟合-ΔSMmax 和相对冷却功率 (RCP)，我们确定它们在沿 c 轴的磁场中的关系为 -ΔSMmax∝Hn (n = 0.694(1)) 和 RCP∝Hm (m = 1.301(3))。对 TC 附近临界行为的进一步分析表明，在 TC = 341.5(1) K 时，临界指数 β = 0.41(1)；在 TC = 341.6(3) K 时，临界指数 γ = 1.01(1)；在 TC = 340 K 时，临界指数 δ = 3.67(15)，表明存在三维复合磁交换。

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引用次数: 0

CBD-synthesized Mg-doped CdS thin films for hybrid solar cells and self-powered photodetectors 用于混合太阳能电池和自供电光电探测器的 CBD 合成掺镁 CdS 薄膜

IF 2.8 3区物理与天体物理 Q2 PHYSICS, CONDENSED MATTER

Physica B-condensed Matter

Pub Date : 2024-10-11 DOI: 10.1016/j.physb.2024.416622

Mg-doped CdS samples were deposited via chemical bath deposition onto fluorine-doped tin oxide slides with varying levels of Mg-doping. Structural analysis revealed improved crystal quality in CdS films upon Mg incorporation. Morphological examinations indicated a reduction in grain size alongside appearance of smooth, void-free surfaces particularly evident at 3 % Mg-doping. Mg-doping also resulted in enhanced transparency of CdS films, notably at 3 % and 5 % within the visible spectrum. Efficient exciton dissociation was observed in hybrid solar cells based on 1 % and 3 % Mg-doped CdS, as evidenced by photoluminescence. Top-performing solar cell achieved an efficiency of 0.220 %, nearly seven times that of control device. 5 % Mg-doped CdS-based photodetectors exhibited favorable photosensing characteristics: a responsivity of 0.011 A/W, detectivity of 4.4 × 10⁸ Jones, external quantum efficiency of 3.1 %, and rise/decay times of 26/25 ms at zero bias. These findings underscore beneficial effects of Mg-doping on both hybrid solar cell and self-driven photodetector performance.

掺杂镁的 CdS 样品是通过化学沉积法沉积在掺氟氧化锡载玻片上的，掺杂镁的程度各不相同。结构分析表明，掺入镁后，CdS 薄膜的晶体质量得到改善。形态学检查显示，晶粒尺寸减小，表面光滑无空隙，这在掺镁 3% 时尤为明显。掺镁还提高了 CdS 薄膜的透明度，尤其是在 3% 和 5% 的可见光谱范围内。光致发光证明，在基于 1% 和 3% 掺镁 CdS 的混合太阳能电池中观察到了高效的激子解离。性能最好的太阳能电池的效率达到了 0.220%，几乎是对照装置的七倍。基于 5 % 掺镁 CdS 的光电探测器表现出良好的光敏特性：响应率为 0.011 A/W，检测率为 4.4 × 108 Jones，外部量子效率为 3.1 %，零偏压下的上升/衰减时间为 26/25 ms。这些发现强调了掺镁对混合太阳能电池和自驱动光电探测器性能的有利影响。

引用次数: 0

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