Journal of Materials Science: Materials in Electronics最新文献

Dielectric ceramic capacitors have received a great deal of attention. In this work, (1-x)[0.92Bi_0.5Na_0.5TiO₃-0.08(0.5Ca_0.3Ba_0.7TiO₃-0.5BaTi_0.8Zr_0.2O₃)]-xNaNbO₃ ceramics were prepared. The breakdown electric field of the ceramics is significantly enhanced, thanks to the rational two-phase (P4bm and R3c) coexistence structure and introduction of NaNbO₃. As a result, a recoverable energy storage density (W_r) of 3.7 J/cm³ and an efficiency (η) of 84.8% are achieved in 0.88[0.92Bi_0.5Na_0.5TiO₃-0.08(0.5Ca_0.3Ba_0.7TiO₃-0.5BaTi_0.8Zr_0.2O₃)]-0.12NaNbO₃ sample. In addition, at 160 °C, the sample has 2.8 J/cm³ of W_r and 92.1% of η at 240 kV/cm. Besides, the sample has excellent power density and rapid charge/discharge capability.

Anion doping offers a promising approach to enhance the ionic conductivity of solid electrolytes at intermediate temperatures, a key factor hindering the widespread commercialization process of solid oxide fuel cells (SOFCs). This study, for the first time, explores the influence of fluorine doping at the concentrations of 0, 5, and 10 mol% in La_0.9Sr_0.1Ga_0.8Mg_0.2O_3-δ (LSGM) perovskite structure, synthesized using the glycine-nitrate combustion method. X-ray diffraction (XRD) analysis revealed a transition from orthorhombic to monoclinic phase upon increasing the fluorine incorporation, while maintaining the tolerance factor near unity, indicating a minimal structural distortion within the GaO₆ octahedra. X-ray photoelectron spectroscopy (XPS) confirmed the successful incorporation of fluorine ions, with an associated enhancement in oxygen vacancy that contributed to improved ionic conductivity. Field-emission scanning electron microscopy (FE-SEM) studies revealed that the 10 mol% fluorine-doped LSGM (LSGMF10) exhibited the largest grain size which facilitated faster oxygen vacancy mobility. The optical measurements indicated a reduced bandgap for LSGMF10 due to the increase in oxygen vacancy concentration. Electrochemical impedance spectroscopy (EIS) demonstrated a remarkable conductivity of 3.8 mS/cm at 600 °C for LSGMF10 (0.24 mS/cm for LSGM) that can be attributed to the synergistic effects of minimal lattice distortion, reduced bandgap energy, and improved grain growth induced by fluorine doping. These findings establish fluorine doping as a promising approach for developing high-performance SOFC electrolytes at intermediate temperatures.

Two series of spinel ferrite nanoparticles Mn_0.5Zn_0.5−xCu_xFe_2−yO₄Gd_y (where x = 0, 0.05, 0.1, 0.15, 0.2, 0.25, y = 0, 0.1) synthesized using the co-precipitation method. The techniques of XRD, FTIR, SEM–EDS, TEM-SAED, and VSM were employed to investigate the microstructural, optical, morphological and magnetic properties of the nanoparticles. The XRD findings validated the establishment of a cubic spinel ferrite structure (Fd-3m space group). Crystallite size for Gd³⁺ substituted NPs was in the range of 15–24 nm and for without Gd³⁺ NPs 15–22 nm with varying Copper concentration. The characteristic absorption bands within the range of 400–4000 cm⁻¹ associated with spinel ferrite were detected using the FTIR technique. SEM examination confirmed that the ferrite particle grains are agglomerated. EDS spectra verified the presence of all included components in the composition. Morphology & size analysis was made by TEM-SAED technique where particles shown nearly spherical shape. The measured mean particle size obtained from TEM corresponds with the crystallite size calculated from XRD data. The M–H hysteresis curve was utilized to compute and evaluate the magnetic properties of nanoparticles. The saturation magnetization (M_s), coercivity (H_c), remanence (M_r), and magnetic moment, in connection to structural and microstructural characteristics. Saturation magnetization varied when the concentration of Cu²⁺ increased, from 7.1 to 43.9 emu/g for Gd³⁺ substituted samples and 4.1 to 31.32 emu/g for Gd³⁺ unsubstituted samples. The measured value of H_c is rather low, suggesting that it can be quickly demagnetized and is suitable for electromagnetic applications.

Fluoropolymers are fascinating in the high-tech industry due to their widespread applications, including fabricating actuators and sensors, controlling and monitoring storage, and energy generation. In this paper, we have communicated the development of an electroactive β-phase in flexible, lightweight, and thermally stable polymer nanocomposite in the configuration of 93% PVDF-7% NiFe₂O₄ by weight percentage fabricated via a cost-effective solution-casting technique. XRD, FTIR, and TGA were performed to check the structural and thermal stability of the system. Low loading of nano-nickel ferrite in the PVDF, the composite developed a substantial electroactive β-phase of 85.85% confirmed from FTIR analysis with enhanced thermal stability of 60.2 °C with respect to PVDF, as evident from the TGA study. FESEM, HRTEM, AFM, EDAX, and elemental mapping have been performed to study the microstructural and surface topology of the developed composite quantitatively and qualitatively. AFM study confirms the size of the spherulitics modulated to 7.4 μm as compared to 2.9 μm of PVDF referred to enhance thermal and mechanical stability along with increased β-phase. UV–visible spectroscopy study reveals the composite’s optical band gap to be 3.46 eV. The ambient condition’s capacitive, resistive, conductive, switching, and magnetic characteristics have been studied to exploit their properties for suitable device inclusion, including flexible electronics. The composite possesses a saturation polarisation of 1.5790 µC/cm², remnant polarisation of 0.3725 µC/cm², and a coercive field of 60.45 kV/cm at room temperature, which is useful for energy storage devices. The room-temperature ferrimagnetism suggests the composite’s application in multifunctional devices with a first-order magneto-electric (α_ME) coefficient of 11 mV/cm.Oe.

The coupling relationship between dielectric constant (ɛ) and breakdown strength (BDS) in poly(vinylidene fluoride) (PVDF)-based dielectric flexible composites was investigated by comparing the effects of one-dimensional (1D) glass fibers with moderate dielectric constants and zero-dimensional (0D) (K,Na)NbO3 (KNN) particles with high dielectric constants. The study aimed to enhance the decoupling degree between ɛ and BDS by optimizing filler composition and morphology. Results showed that glass fibers promoted the α to γ phase transition in PVDF, enhancing both ɛ and BDS over a broad filler content range (0 ~ 6 vol.%). Specifically, ɛ increased by up to 105%, and BDS reached a maximum of 2620 kV/mm. In contrast, KNN particles rapidly increased ɛ but reduced the decoupling degree due to the quick α to β phase transformation and strong interfacial polarization. The study concludes that optimizing filler morphology and dielectric properties is crucial for developing PVDF-based composites with high energy storage density. Future work should explore other fillers and composite structures to further enhance the decoupling effect and develop advanced dielectric materials for high-performance applications.

In this study, a memristor structure known as a missing circuit element was produced. This study consists of a total of six samples in both thin film and device form with different arrays of BST film and CeO₂ film on SiO₂/Si substrate. The effects of different arrays and device forms of these two films on memristive behavior were investigated. It was observed that the structures exhibited memristive behavior due to the difference in ion mobility in films with different dielectric constants. It was also observed that the structures changed their memristive behavior in the annealing process performed at different temperatures. It was observed that the memristive behaviors examined imitated the connection strength of artificial synapses, and they are suitable for the production of multi-bit memristors or analog memristors suitable for the creation of artificial neuromorphic networks.

This article presents a successful fabrication method for hemispheric SiGe nanocrystal-based Mie resonators on photoactive silicon nanodisks on an insulator, achieved through an innovative and scalable approach. This method combines solid-state dewetting of an ultra-thin silicon-on-insulator film (UT-SOI) with germanium growth via molecular beam epitaxy (MBE). The results demonstrate the formation of Mie resonators on silicon nanodisks with precisely defined hemispherical shapes and a homogeneous distribution of germanium in the SiGe core. Three-dimensional finite-difference time-domain (3D FDTD) simulations of the optical properties of SiGe/Si Mie resonators emphasize their capability to generate very high optical loss. This discovery sets the stage for designing compact and high-performance photodetectors with efficient photoactive silicon nanodisks. Moreover, post-integration electrical characterization of these Mie resonators in a MIS-type photodetector reveals their ability to induce a photovoltaic effect while preserving fundamental electrical characteristics. These findings represent a significant advancement in both the fabrication and integration of SiGe-based Mie resonators into optoelectronic devices, opening new avenues in the realms of integrated photonics and advanced optoelectronic technologies.

Impact of partial substitution of Sn by Cu on the mechanical, electrical, and magnetic properties of Ni₄₄Mn₄₄Sn₁₂ Heusler alloys was analyzed in this study. The alloys Ni₄₄Mn₄₄Sn₁₂, Ni₄₄Mn₄₄Sn_10.5Cu_1.5, and Ni₄₄Mn₄₄Sn₉Cu₃ were produced through casting without atmosphere control and characterized using microscopy scanning electron microscopy, X-ray diffraction, Vickers microhardness tests, electrical resistivity measurements, and vibrating sample magnetometry. The results showed that the partial substitution of Sn with Cu did not affect the solidification microstructure or the phases present at room temperature. However, this substitution increased the transition temperatures from austenite to martensite and from martensite to austenite, increasing the proportion of the martensitic phase from 56.04 to 77.67%. This resulted in a decrease in Vickers microhardness (from 468.3 to 352.3 HV), electrical resistivity (from 1.3 to 1.16 mΩ∙mm), and saturation magnetization (from 23.67 to 9.6 emu/g). In contrast, both coercivity and remanent magnetization rose, with values changing from 5.37 to 21.64 Oe and from 0.16 to 0.31 emu/g, respectively. Thus, our findings present a new approach for doping the NiMnSn alloy, aimed at modifying its structural and electrical properties, which are important factors for technological applications.

The g-C₃N₄/MXene heterojunction photocatalyst was effectively developed using the wet impregnation synthesis method, and its physicochemical properties were thoroughly characterised. The composites of the g-C₃N₄/MXene was prepared by mixing the MXene to varies amount of g-C₃N₄ (0.1–1.2 wt.%). MXene with 0.4 wt.% g-C₃N₄ exhibited the optimal loading on the photocatalytic degradation of methylene blue under visible light, with a degradation efficiency of > 99% within 150 min. XRD, FTIR, FESEM, SAP, and DR-UV-Vis were utilised to characterise the g-C₃N₄/MXene heterojunction photocatalyst as developed. It was discovered that the introduction of g-C₃N₄ affects the oxygenated functional groups and increases photocatalytic activity by increasing the density of free carrier electrons and inhibiting electron–hole recombination. However, it was revealed that excessive concentration of g-C₃N₄ can significantly inhibit photocatalytic activity. The FESEM-EDX analysis revealed Al element was decreased up to 70% for 0.4GM thus increase the intervals between the MXene layers with higher exposed oxygen active sites for photocatalytic degradation. Corresponds to that, 0.4GM has the highest oxygen active sites for g-C₃N₄/MXene heterostructure photocatalyst which was 6.1 wt.%. The findings of this study may provide an innovative approach for enhancing the photocatalytic activity of MXene for applications requiring highly effective effluent treatment.

This paper presents the preparation of ceramics with (Bi_0.4Ba_0.1)Na_0.5TiO₃ via a conventional solid-state reaction method and their sintering at low temperatures of 850, 900, and 950 °C for 3 h, respectively. Bi₂O₃ and Na₂O₃ were used to suppress the volatility of Bi and Na ions during the sintering of (Bi_0.4Ba_0.1)Na_0.5TiO₃ ceramics. X-ray diffraction (XRD), Scanning electron microscope (SEM), and an LCR meter were used to analyze these ceramics' structural, morphological, and dielectric properties. Rhombohedral crystal lattice (with space group R3c) is confirmed by Rietveld’s refinement of the XRD pattern. W–H plots show an increase in crystallite strain from 0.77 × 10^–3 to 1.5 × 10^–3 due to a decrease in average crystallite size from 133.32 to 119.52 nm. With an increase in sintering temperature, the grain size increased from 0.55 to 2.30 μm on average based on SEM images. Dielectric spectra revealed that the magnitude of the dielectric constant (ε) decreases with frequency increase and is explained by Maxwell–Wagner’s Model. The ferroelectric phase transition temperature is shifted to a higher temperature, which makes the material feasible for energy storage applications.