Pub Date : 2025-09-30DOI: 10.1016/j.cap.2025.09.026
Tsung-Wei Zeng, Shih-Jie Mai
Silica nanoparticles were combined with the polymeric binder poly(vinylpyrrolidone) (PVP) to fabricate antireflection (AR) films on a poly(ethylene terephthalate) (PET) substrate. To study the flexibility of the AR films, their optical properties and morphologies were measured before and after 100 successive bending tests. After bending, the changes in transmittance and reflectance spectra were significantly reduced for AR coatings containing PVP. SEM images revealed that incorporating PVP reduced defects in spin-coated AR films and helped prevent severe structural deterioration after successive bending cycles.
{"title":"Improvement of the flexibility of silica nanoparticle antireflection coatings by incorporating a poly(vinylpyrrolidone) binder","authors":"Tsung-Wei Zeng, Shih-Jie Mai","doi":"10.1016/j.cap.2025.09.026","DOIUrl":"10.1016/j.cap.2025.09.026","url":null,"abstract":"<div><div>Silica nanoparticles were combined with the polymeric binder poly(vinylpyrrolidone) (PVP) to fabricate antireflection (AR) films on a poly(ethylene terephthalate) (PET) substrate. To study the flexibility of the AR films, their optical properties and morphologies were measured before and after 100 successive bending tests. After bending, the changes in transmittance and reflectance spectra were significantly reduced for AR coatings containing PVP. SEM images revealed that incorporating PVP reduced defects in spin-coated AR films and helped prevent severe structural deterioration after successive bending cycles.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"80 ","pages":"Pages 300-305"},"PeriodicalIF":3.1,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145262497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-30DOI: 10.1016/j.cap.2025.09.027
R. Castelo , M. Cota-Leal , J.A. Reynoso-Hernández , C. Vásquez-López , A. Olivas
In this study, zinc sulfide (ZnS) nanoparticles were synthesized via a gas-liquid sulfidation process and incorporated into cellulose acetate (CA) nanofibers through electrospinning to fabricate composite photocatalytic materials for the degradation of methylene blue (MB) in water. The nanoparticles and resulting nanofibers were characterized to confirm their structural, morphological, and chemical properties. The ZnS/CA nanofibers exhibited high photocatalytic activity under ultraviolet (UV) irradiation and retained their activity over multiple degradation cycles. Toxicity assays using fibroblast cells demonstrated that the composite nanofibers did not induce toxic effects, highlighting their potential for environmentally safe water treatment applications.
{"title":"Electrospun zinc sulfide/cellulose acetate nanofiber composite with enhanced photocatalytic activity and reusability for methylene blue degradation","authors":"R. Castelo , M. Cota-Leal , J.A. Reynoso-Hernández , C. Vásquez-López , A. Olivas","doi":"10.1016/j.cap.2025.09.027","DOIUrl":"10.1016/j.cap.2025.09.027","url":null,"abstract":"<div><div>In this study, zinc sulfide (ZnS) nanoparticles were synthesized via a gas-liquid sulfidation process and incorporated into cellulose acetate (CA) nanofibers through electrospinning to fabricate composite photocatalytic materials for the degradation of methylene blue (MB) in water. The nanoparticles and resulting nanofibers were characterized to confirm their structural, morphological, and chemical properties. The ZnS/CA nanofibers exhibited high photocatalytic activity under ultraviolet (UV) irradiation and retained their activity over multiple degradation cycles. Toxicity assays using fibroblast cells demonstrated that the composite nanofibers did not induce toxic effects, highlighting their potential for environmentally safe water treatment applications.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"80 ","pages":"Pages 273-281"},"PeriodicalIF":3.1,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145262494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-26DOI: 10.1016/j.cap.2025.09.024
Muhammad Arif , Donghun Han , Won Chan Shin , Seunghun Cha , Young-Kwang Kim , Sang Woo Kim , Bo Wha Lee , Muhammad Awais , Dongwhi Choi , Jong-Soo Rhyee
Soft magnetic materials are essential components in applications of motors, generators, transformers, and many electronic devices. Here we present the improved soft magnetic properties in Fe-6.5 wt%Si/(TiO2:Fe)(nano powder; NP) soft magnetic composite (SMC) cores with varying concentrations of Fe nanopowders (0–4 wt%) synthesized by hot-press sintering. Increasing Fe nanopowder concentration significantly increases the density and electrical resistivity by filling the airgap and grain boundary scattering of carriers, respectively. Furthermore, adding Fe nanopowders leads to remarkably low coercivity (<15 Oe) and high saturation magnetization (189.5 emu/g). Notably, the FeSi/(TiO2:Fe)(NP) SMCs exhibited excellent soft magnetic characteristics, including high permeability with good frequency stability ranging from 0 to 1 MHz and ultra-low eddy current loss (8.16 kW/m3 decreased by 83.47 %) at the 2 wt% doping concentration of Fe nanopowder. The composite with 3 wt% Fe nanopowder showed a significant decrease in hysteresis loss Ph with a minimum value of around 0.677 kW/m3. Therefore, the appropriate incorporation of Fe nanopowders, combined with the hot-press sintering technique, effectively reduces core loss, particularly eddy current loss, indicating that the Fe NP composites with FeSi matrix are highly promising for high-power and high-frequency electronic applications.
{"title":"Extremely low core-loss and enhanced permeability stability in hot press sintered FeSi soft magnetic composites by TiO2 and Fe nanopowders air gap filling","authors":"Muhammad Arif , Donghun Han , Won Chan Shin , Seunghun Cha , Young-Kwang Kim , Sang Woo Kim , Bo Wha Lee , Muhammad Awais , Dongwhi Choi , Jong-Soo Rhyee","doi":"10.1016/j.cap.2025.09.024","DOIUrl":"10.1016/j.cap.2025.09.024","url":null,"abstract":"<div><div>Soft magnetic materials are essential components in applications of motors, generators, transformers, and many electronic devices. Here we present the improved soft magnetic properties in Fe-6.5 wt%Si/(TiO<sub>2</sub>:Fe)(nano powder; NP) soft magnetic composite (SMC) cores with varying concentrations of Fe nanopowders (0–4 wt%) synthesized by hot-press sintering. Increasing Fe nanopowder concentration significantly increases the density and electrical resistivity by filling the airgap and grain boundary scattering of carriers, respectively. Furthermore, adding Fe nanopowders leads to remarkably low coercivity (<15 Oe) and high saturation magnetization (189.5 emu/g). Notably, the FeSi/(TiO<sub>2</sub>:Fe)(NP) SMCs exhibited excellent soft magnetic characteristics, including high permeability with good frequency stability ranging from 0 to 1 MHz and ultra-low eddy current loss (8.16 kW/m<sup>3</sup> decreased by 83.47 %) at the 2 wt% doping concentration of Fe nanopowder. The composite with 3 wt% Fe nanopowder showed a significant decrease in hysteresis loss <em>P</em><sub>h</sub> with a minimum value of around 0.677 kW/m<sup>3</sup>. Therefore, the appropriate incorporation of Fe nanopowders, combined with the hot-press sintering technique, effectively reduces core loss, particularly eddy current loss, indicating that the Fe NP composites with FeSi matrix are highly promising for high-power and high-frequency electronic applications.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"80 ","pages":"Pages 242-249"},"PeriodicalIF":3.1,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145226939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the present work, thermoelectric parameters electrical conductivity, Seebeck coefficient and power factor of β-Zn4Sb3 thin films at room temperature (303 K) were enhanced by 102.56 %, 110.90 % and 712.76 % respectively using post-deposition thermal annealing approach. Multiphase Rietveld refinement analysis was implemented to determine phase quantification, lattice parameters, atomic positions and occupancies, bond lengths & angles and crystal structure of the synthesized material. Maximum electrical conductivity, Seebeck coefficient and power factor values of , 232 and 764 at 303 K were obtained after annealing of thermally evaporated β-Zn4Sb3 thin films for 6 h. Enhancement in electrical conductivity values were attributed to lowered band gap values, reduced defects & grain boundaries, large crystallite sizes and reorientation of growth direction caused by annealing. Enhancement in Seebeck coefficient values were attributed to the energy filtering effects promoted by increasing surface roughness. Structural characteristics of thin films were investigated, revealing reorientation of crystallites growth direction via thermal annealing. Investigation of optical characteristics revealed a band gap energy value of 1.28 eV for without annealed β-Zn4Sb3 thin film. Morphological properties of thin film surfaces revealed aggregation of grains due to annealing at elevated temperatures and average thin film thickness of 323 nm was determined. Topographical characteristics of thin films were investigated to visualize 3D surface maps, line profile and determine surface roughness.
{"title":"Thermal annealing induced multifold enhancement in thermoelectric power factor of β-Zn4Sb3 thin films","authors":"Avinash Kumar , Nirmal Manyani , Janpreet Singh , S.K. Tripathi","doi":"10.1016/j.cap.2025.09.014","DOIUrl":"10.1016/j.cap.2025.09.014","url":null,"abstract":"<div><div>In the present work, thermoelectric parameters electrical conductivity, Seebeck coefficient and power factor of β-Zn<sub>4</sub>Sb<sub>3</sub> thin films at room temperature (303 K) were enhanced by 102.56 %, 110.90 % and 712.76 % respectively using post-deposition thermal annealing approach. Multiphase Rietveld refinement analysis was implemented to determine phase quantification, lattice parameters, atomic positions and occupancies, bond lengths & angles and crystal structure of the synthesized material. Maximum electrical conductivity, Seebeck coefficient and power factor values of <span><math><mrow><mn>1.58</mn><mo>×</mo><msup><mn>10</mn><mn>4</mn></msup><mspace></mspace><mi>S</mi><msup><mi>m</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span>, 232 <span><math><mrow><mi>μ</mi><mi>V</mi><msup><mi>K</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span> and 764 <span><math><mrow><mi>μ</mi><mi>W</mi><msup><mi>m</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup><msup><mi>K</mi><mrow><mo>−</mo><mn>2</mn></mrow></msup></mrow></math></span> at 303 K were obtained after annealing of thermally evaporated β-Zn<sub>4</sub>Sb<sub>3</sub> thin films for 6 h. Enhancement in electrical conductivity values were attributed to lowered band gap values, reduced defects & grain boundaries, large crystallite sizes and reorientation of growth direction caused by annealing. Enhancement in Seebeck coefficient values were attributed to the energy filtering effects promoted by increasing surface roughness. Structural characteristics of thin films were investigated, revealing reorientation of crystallites growth direction via thermal annealing. Investigation of optical characteristics revealed a band gap energy value of 1.28 eV for without annealed β-Zn<sub>4</sub>Sb<sub>3</sub> thin film. Morphological properties of thin film surfaces revealed aggregation of grains due to annealing at elevated temperatures and average thin film thickness of 323 nm was determined. Topographical characteristics of thin films were investigated to visualize 3D surface maps, line profile and determine surface roughness.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"80 ","pages":"Pages 311-326"},"PeriodicalIF":3.1,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145262493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-24DOI: 10.1016/j.cap.2025.09.021
F. Chen , C.F. Sánchez-Valdés , F.H. Chen , Y.X. Tong , L. Li
Ni-Co-Mn-Sn alloys with a significant magnetocaloric effect are considered promising candidates for room-temperature magnetic refrigeration. Alloying serves as an effective method to tune the working temperature and magnetocaloric properties of Ni-Co-Mn-Sn alloys. Here, we report the phase transformation and magnetocaloric properties of polycrystalline Ni39Co7Mn43Sn7Ti4 by alloying with a relatively high Ti content. This alloy displays a first-order martensitic transformation (MT) near room temperature and a second-order magnetic transition in austenite at 366 K. The application of a magnetic field significantly widened the temperature range of the MT, thereby contributing to a substantial effective refrigeration capacity of 198 J kg−1 at a magnetic field change of 5 T. Moreover, the alloy exhibits simultaneously a moderate isothermal magnetic entropy change (12.2 J kg−1K−1) and a low average hysteresis loss (40 J kg−1) due to the weakened magnetic field-induced reverse martensitic transformation caused by Ti alloying.
{"title":"Low hysteresis loss and moderate magnetic entropy change near room temperature in the bulk Ni39Co7Mn43Sn7Ti4 alloy","authors":"F. Chen , C.F. Sánchez-Valdés , F.H. Chen , Y.X. Tong , L. Li","doi":"10.1016/j.cap.2025.09.021","DOIUrl":"10.1016/j.cap.2025.09.021","url":null,"abstract":"<div><div>Ni-Co-Mn-Sn alloys with a significant magnetocaloric effect are considered promising candidates for room-temperature magnetic refrigeration. Alloying serves as an effective method to tune the working temperature and magnetocaloric properties of Ni-Co-Mn-Sn alloys. Here, we report the phase transformation and magnetocaloric properties of polycrys<strong>talline Ni<sub>39</sub>Co<sub>7</sub>Mn<sub>43</sub>Sn<sub>7</sub>Ti<sub>4</sub> by alloying with a relatively high Ti content. This alloy displays a first-order martensitic transformation (MT) near room temperature and a second-order magnetic transition in austenite at 366 K. The application of a magnetic field significantly widened the temperature range of the MT, thereby contributing to a substantial effective refrigeration capacity of 198 J kg<sup>−1</sup> at a magnetic field change of 5 T. Moreover, the alloy exhibits simultaneously a moderate isothermal magnetic entropy change (12.2 J kg<sup>−1</sup></strong> <strong>K<sup>−1</sup>) and a low average hysteresis loss (40 J kg<sup>−1</sup>) due to the weakened magnetic field-induced reverse martensitic transformation caused by Ti alloying</strong>.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"80 ","pages":"Pages 213-218"},"PeriodicalIF":3.1,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145154823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-24DOI: 10.1016/j.cap.2025.09.005
Sang-Hee Lee, Seung-Won Oh
We report an ultra-broadband and voltage-tunable polarization rotator based on a hybrid aligned nematic (HAN) liquid crystal cell with an intentional pre-twisted configuration. By employing a rubbing angle of ∼130° between the planar and vertical alignment layers, an initial twist angle of ∼30° is formed even in the absence of an external field. Applying a vertical electric field gradually lowers the polar angle of the LC molecules while preserving their azimuthal twist, thereby increasing their contribution to polarization rotation. The proposed structure achieves a continuous rotation of the polarization vector from 0° to 90° over a wavelength range of 200–2000 nm with a degree of linear polarization (DoLP) exceeding 0.9. Compared with previous approaches, this design operates at a significantly lower driving voltage (∼10 V) and eliminates the need for patterned electrodes, enhancing its compatibility with large-area and low-cost fabrication. The optical response is supported by director simulations and Jones matrix calculations, highlighting the physical mechanisms underlying its broadband and tunable polarization control.
{"title":"Pre-twisted hybrid LC polarization rotator with ultra-broadband and low-voltage operation","authors":"Sang-Hee Lee, Seung-Won Oh","doi":"10.1016/j.cap.2025.09.005","DOIUrl":"10.1016/j.cap.2025.09.005","url":null,"abstract":"<div><div>We report an ultra-broadband and voltage-tunable polarization rotator based on a hybrid aligned nematic (HAN) liquid crystal cell with an intentional pre-twisted configuration. By employing a rubbing angle of ∼130° between the planar and vertical alignment layers, an initial twist angle of ∼30° is formed even in the absence of an external field. Applying a vertical electric field gradually lowers the polar angle of the LC molecules while preserving their azimuthal twist, thereby increasing their contribution to polarization rotation. The proposed structure achieves a continuous rotation of the polarization vector from 0° to 90° over a wavelength range of 200–2000 nm with a degree of linear polarization (DoLP) exceeding 0.9. Compared with previous approaches, this design operates at a significantly lower driving voltage (∼10 V) and eliminates the need for patterned electrodes, enhancing its compatibility with large-area and low-cost fabrication. The optical response is supported by director simulations and Jones matrix calculations, highlighting the physical mechanisms underlying its broadband and tunable polarization control.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"80 ","pages":"Pages 219-223"},"PeriodicalIF":3.1,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145154822","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-24DOI: 10.1016/j.cap.2025.09.022
Liyan Li , Daifeng Zou , Weiyao Jia , Shuhong Xie
Two-dimensional (2D) multiferroic van der Waals (vdW) heterostructures, combining ferroelectricity and ferromagnetism, offer unprecedented opportunities for next-generation spintronic and memory devices. However, achieving strong magnetoelectric coupling and room-temperature stability remains a significant challenge. Here, we investigate the polarization-mediated electromagnetic and transport properties of the MnSe2/Al2S3 vdW heterostructure using first-principles density functional theory calculations. Our results demonstrate robust perpendicular magnetic anisotropy and electrically tunable interfacial charge transfer, enabling reversible switching between Schottky-barrier-limited and metallic conduction regimes. Remarkably, the ferroelectric polarization reversal in Al2S3 induces a substantial tunneling electroresistance (TER) effect, with a ratio reaching 3.18 × 103 %, highlighting its potential for non-volatile memory applications. Furthermore, the system exhibits enhanced thermal stability, with Curie temperatures of ∼203 K and ∼153 K under up polarized and down polarized states, surpassing those of many 2D ferromagnetic materials. These findings establish the MnSe2/Al2S3 heterostructure as a promising platform for multifunctional spintronic devices, providing critical insights into the design of high-performance, energy-efficient nanoelectronics through interfacial magnetoelectric coupling.
{"title":"Polarization-mediated electromagnetic and transport properties of multiferroic MnSe2/Al2S3 van der Waals heterostructures","authors":"Liyan Li , Daifeng Zou , Weiyao Jia , Shuhong Xie","doi":"10.1016/j.cap.2025.09.022","DOIUrl":"10.1016/j.cap.2025.09.022","url":null,"abstract":"<div><div>Two-dimensional (2D) multiferroic van der Waals (vdW) heterostructures, combining ferroelectricity and ferromagnetism, offer unprecedented opportunities for next-generation spintronic and memory devices. However, achieving strong magnetoelectric coupling and room-temperature stability remains a significant challenge. Here, we investigate the polarization-mediated electromagnetic and transport properties of the MnSe<sub>2</sub>/Al<sub>2</sub>S<sub>3</sub> vdW heterostructure using first-principles density functional theory calculations. Our results demonstrate robust perpendicular magnetic anisotropy and electrically tunable interfacial charge transfer, enabling reversible switching between Schottky-barrier-limited and metallic conduction regimes. Remarkably, the ferroelectric polarization reversal in Al<sub>2</sub>S<sub>3</sub> induces a substantial tunneling electroresistance (TER) effect, with a ratio reaching 3.18 × 10<sup>3</sup> %, highlighting its potential for non-volatile memory applications. Furthermore, the system exhibits enhanced thermal stability, with Curie temperatures of ∼203 K and ∼153 K under up polarized and down polarized states, surpassing those of many 2D ferromagnetic materials. These findings establish the MnSe<sub>2</sub>/Al<sub>2</sub>S<sub>3</sub> heterostructure as a promising platform for multifunctional spintronic devices, providing critical insights into the design of high-performance, energy-efficient nanoelectronics through interfacial magnetoelectric coupling.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"80 ","pages":"Pages 234-241"},"PeriodicalIF":3.1,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145154826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-23DOI: 10.1016/j.cap.2025.09.020
A-Young Moon , Ho Seok Kim , Jong Geun Bae , Deog Gyun Cho , Woon-Yong Park , Se Youn Moon
Ablation-resistant zirconium carbide (ZrC) layers were coated onto carbon/carbon (C/C) composites using vacuum plasma spraying. The structural and ablative characteristics of ZrC layers applied in single-versus multi-step coating processes were compared. An increase in the number of coating cycles from 4 to 20 in single-step coating increased the ZrC layer's thickness from 32.3 μm to 116.2 μm even though the coating rate per cycle was reduced from 8.1 μm/cycle to 5.8 μm/cycle. By increasing the number of cycles, the substrate surface was continuously heated, enhancing the lateral spread of molten droplets and improving the porosity and hardness of the ZrC layer. On the other hand, multi-step coating, involving repetition of the single-step process, yielded a 20% thickness increase of ZrC layers with a higher coating rate while maintaining comparable mechanical properties despite an identical total number of coating cycles. Furthermore, the multi-step-coated layers showed better thermal oxidation resistance than the single-step-coated layers due to the formation of ZrC/ZrC interfaces having larger grain boundaries and the thicker ZrCxOy layers, effectively barring oxygen diffusion. The multi-step coating of identical ZrC layers suggested the better thermal oxidation resistant protection way for C/C composite without the reduction of coated layer's properties.
{"title":"Structural properties and ablation behaviors of homogeneous ZrC multi-layer coated on carbon/carbon composites via a multi-step vacuum plasma spray coating process","authors":"A-Young Moon , Ho Seok Kim , Jong Geun Bae , Deog Gyun Cho , Woon-Yong Park , Se Youn Moon","doi":"10.1016/j.cap.2025.09.020","DOIUrl":"10.1016/j.cap.2025.09.020","url":null,"abstract":"<div><div>Ablation-resistant zirconium carbide (ZrC) layers were coated onto carbon/carbon (C/C) composites using vacuum plasma spraying. The structural and ablative characteristics of ZrC layers applied in single-versus multi-step coating processes were compared. An increase in the number of coating cycles from 4 to 20 in single-step coating increased the ZrC layer's thickness from 32.3 μm to 116.2 μm even though the coating rate per cycle was reduced from 8.1 μm/cycle to 5.8 μm/cycle. By increasing the number of cycles, the substrate surface was continuously heated, enhancing the lateral spread of molten droplets and improving the porosity and hardness of the ZrC layer. On the other hand, multi-step coating, involving repetition of the single-step process, yielded a 20% thickness increase of ZrC layers with a higher coating rate while maintaining comparable mechanical properties despite an identical total number of coating cycles. Furthermore, the multi-step-coated layers showed better thermal oxidation resistance than the single-step-coated layers due to the formation of ZrC/ZrC interfaces having larger grain boundaries and the thicker ZrC<sub>x</sub>O<sub>y</sub> layers, effectively barring oxygen diffusion. The multi-step coating of identical ZrC layers suggested the better thermal oxidation resistant protection way for C/C composite without the reduction of coated layer's properties.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"80 ","pages":"Pages 194-203"},"PeriodicalIF":3.1,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145154829","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-23DOI: 10.1016/j.cap.2025.09.007
V.T. Thrivikraman, K. Sudheendran
The structural, electrical, and optical properties of bismuth (Bi) and antimony (Sb) co-doped potassium sodium niobate (KNN) ceramics were systematically investigated with a focus on their potential for energy harvesting and optoelectronic applications. X-ray diffraction (XRD) analysis revealed notable structural modifications, including the presence of a secondary phase, indicating successful incorporation of dopants and associated lattice distortions. Scanning electron microscopy (SEM) demonstrated a reduction in grain size and the formation of dense microstructures, while energy-dispersive X-ray spectroscopy (EDS) confirmed the chemical homogeneity and purity of the synthesized ceramics.
Optical characterization using UV–Vis spectroscopy showed a narrowing of the band gap and enhanced transparency in the near-infrared region. Notably, the wavelength of maximum transmittance exhibited a red shift from approximately 400 nm–650 nm. Photoluminescence (PL) measurements revealed prominent blue-green emissions, which were attributed to defect-related electronic transitions, underscoring the influence of structural and electronic defects introduced by co-doping.
Dielectric properties were assessed using impedance spectroscopy, revealing an enhancement in the dielectric constant and overall energy conversion efficiency. The findings suggest that Bi and Sb co-doping effectively tailors the multifunctional properties of KNN ceramics, thereby enhancing their suitability for next-generation energy harvesting and optoelectronic devices.
{"title":"Structural, electrical and optical properties of pure KNN and bismuth, antimony co-doped KNN ceramics (KNN – Bi, Sb)","authors":"V.T. Thrivikraman, K. Sudheendran","doi":"10.1016/j.cap.2025.09.007","DOIUrl":"10.1016/j.cap.2025.09.007","url":null,"abstract":"<div><div>The structural, electrical, and optical properties of bismuth (Bi) and antimony (Sb) co-doped potassium sodium niobate (KNN) ceramics were systematically investigated with a focus on their potential for energy harvesting and optoelectronic applications. X-ray diffraction (XRD) analysis revealed notable structural modifications, including the presence of a secondary phase, indicating successful incorporation of dopants and associated lattice distortions. Scanning electron microscopy (SEM) demonstrated a reduction in grain size and the formation of dense microstructures, while energy-dispersive X-ray spectroscopy (EDS) confirmed the chemical homogeneity and purity of the synthesized ceramics.</div><div>Optical characterization using UV–Vis spectroscopy showed a narrowing of the band gap and enhanced transparency in the near-infrared region. Notably, the wavelength of maximum transmittance exhibited a red shift from approximately 400 nm–650 nm. Photoluminescence (PL) measurements revealed prominent blue-green emissions, which were attributed to defect-related electronic transitions, underscoring the influence of structural and electronic defects introduced by co-doping.</div><div>Dielectric properties were assessed using impedance spectroscopy, revealing an enhancement in the dielectric constant and overall energy conversion efficiency. The findings suggest that Bi and Sb co-doping effectively tailors the multifunctional properties of KNN ceramics, thereby enhancing their suitability for next-generation energy harvesting and optoelectronic devices.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"80 ","pages":"Pages 250-255"},"PeriodicalIF":3.1,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145226827","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-23DOI: 10.1016/j.cap.2025.09.023
Yanchun Hu, Ying Zhao, Wenke Ma, Xianwei Wang
As an important energy storage device, dielectric capacitor plays an irreplaceable role in modern electronic and power systems because of its characteristics of fast charging, high output, long life and high temperature stability. Among various dielectric materials, Bi0.5Na0.5TiO3-based energy storage ceramics with high saturation polarization are limited due to high conductivity and high residual polarization. In this paper, Bi(0.5-x)Na0.5LaxTiO3 (denoted as BNLxT) ceramic was prepared by solid state reaction method. By introducing La3+ at A position, the Bi0.5Na0.5TiO3-based lead-free ceramic was modified to improve its relaxation characteristics and breakdown strength, so as to achieve the purpose of increasing energy storage density and energy storage efficiency. The introduction of La3+ at A position creates a wide temperature platform between dielectric anomalies, indicating that La3+ can effectively induce the relaxation characteristics of BNT ceramics. The breakdown strength is increased from 136 kV/cm of pure BNT ceramics to 198 kV/cm of Bi0.455Na0.5La0.045TiO3 ceramics, which is 1.46 times higher than before. The residual polarization decreased from 49.24 μC/cm2 to 35.29 μC/cm2, and the effective energy storage density increased from 0.80J/cm3 to 2.07J/cm3, an increase of 2.58 times than before. In addition, the energy storage efficiency achieved a transformation of 10.39 %–26.87 %, which is 2.59 times higher than pure BNT. The results show that La3+ can effectively induce the relaxation characteristics of BNT ceramics, improve the effective energy storage density and energy storage efficiency, and is a good dopant to optimize the energy storage performance of BNT-based ceramics, providing feasibility for optimizing the energy storage performance of BNT-based ceramics.
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