It is shown, that an ultra-low-power voltage controlled oscillator, realized with conventional NAND gates in ring-oscillator configuration, can be operated by a series connected pair of commercial Silicon pin solar cells, only irradiated by a high energy proton beam as power supply. However a very fast degradation of the solar cells is observed, leading to a stop of the oscillator operation after a very short time. By monitoring the oscillator frequency changes when the stack of photodiodes, in this case illuminated with weak ambient light, is not directly exposed to the proton beam but positioned in different positions close to the proton beam, an evaluation of the off-beam-axis irradiation damage could be done. A detailed electrical analysis of the photodiode properties before and after the direct proton irradiation has been added.
{"title":"A nanowatt oscillator powered only by 68 MeV proton irradiation of a crystalline silicon photodiode pair","authors":"Heinz-Christoph Neitzert , Arpana Singh , Alina Hanna Dittwald , Georgios Kourkafas","doi":"10.1016/j.cap.2025.10.004","DOIUrl":"10.1016/j.cap.2025.10.004","url":null,"abstract":"<div><div>It is shown, that an ultra-low-power voltage controlled oscillator, realized with conventional NAND gates in ring-oscillator configuration, can be operated by a series connected pair of commercial Silicon pin solar cells, only irradiated by a high energy proton beam as power supply. However a very fast degradation of the solar cells is observed, leading to a stop of the oscillator operation after a very short time. By monitoring the oscillator frequency changes when the stack of photodiodes, in this case illuminated with weak ambient light, is not directly exposed to the proton beam but positioned in different positions close to the proton beam, an evaluation of the off-beam-axis irradiation damage could be done. A detailed electrical analysis of the photodiode properties before and after the direct proton irradiation has been added.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"80 ","pages":"Pages 306-310"},"PeriodicalIF":3.1,"publicationDate":"2025-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145262498","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 : 2025-10-06DOI: 10.1016/j.cap.2025.10.002
Thi Bich Ngoc Nguyen , Thi Hong Nhung Vu , Anshula Tandon, Sungjin Lee, Yeonju Nam, Sung Ha Park
DNA-based algorithmic self-assembly provides a versatile platform for parallel computation and nanoscale pattern generation. Logic gates constructed from DNA rule tiles enable programmable lattices capable of performing complex mathematical operations. Here, we present a combinatorial method for generating diverse algorithmic patterns using 3-input 1-output logic rules. By combining complementary rule sets (e.g., {R017, R238}) and non-complementary sets (e.g., {R019, R238}), we designed specific rule and operator tiles that reduce the number of unique tiles required while expanding the range of implementable logic functions. The resulting DNA lattices were experimentally validated using atomic force microscopy, and observed patterns closely matched theoretical predictions, demonstrating high fidelity and reliability. This approach improves scalability and efficiency compared with conventional single-rule assemblies and provides a practical route toward constructing complex computational architectures at the nanoscale, with potential applications in molecular computing, programmable nanomaterials, and DNA-based information processing.
{"title":"Scalable assembly of algorithmic DNA lattices using combined 3-input logic rules","authors":"Thi Bich Ngoc Nguyen , Thi Hong Nhung Vu , Anshula Tandon, Sungjin Lee, Yeonju Nam, Sung Ha Park","doi":"10.1016/j.cap.2025.10.002","DOIUrl":"10.1016/j.cap.2025.10.002","url":null,"abstract":"<div><div>DNA-based algorithmic self-assembly provides a versatile platform for parallel computation and nanoscale pattern generation. Logic gates constructed from DNA rule tiles enable programmable lattices capable of performing complex mathematical operations. Here, we present a combinatorial method for generating diverse algorithmic patterns using 3-input 1-output logic rules. By combining complementary rule sets (e.g., {R017, R238}) and non-complementary sets (e.g., {R019, R238}), we designed specific rule and operator tiles that reduce the number of unique tiles required while expanding the range of implementable logic functions. The resulting DNA lattices were experimentally validated using atomic force microscopy, and observed patterns closely matched theoretical predictions, demonstrating high fidelity and reliability. This approach improves scalability and efficiency compared with conventional single-rule assemblies and provides a practical route toward constructing complex computational architectures at the nanoscale, with potential applications in molecular computing, programmable nanomaterials, and DNA-based information processing.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"80 ","pages":"Pages 333-340"},"PeriodicalIF":3.1,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145332808","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 : 2025-10-02DOI: 10.1016/j.cap.2025.09.025
C.Y. Lee, J.H. Han, Y.S. Lee
We investigate the optical thermometric performance of Er3+-doped perovskite oxides with thermally coupled levels (TCLs). We obtain their optical thermometric parameters, such as their fluorescence intensity ratio and temperature sensitivity, from upconversion luminescence spectra under 980 nm excitation over a wide temperature range. Subsequently, we systematically compare these experimentally determined parameters with theoretical predictions for a TCL system, in addition to parameters derived from Judd–Ofelt (J–O) analysis, which is a well-established theoretical framework that describes the radiative transitions and intensities of rare-earth (RE) ions. A close correspondence between the experimental and theoretical results is achieved when the temperature-dependent variation of the J–O parameters and the TCL gap is considered. Our findings provide valuable insights into the roles of host-lattice effects, local crystal field variations, and defect-related phenomena in governing the thermal response of RE ion-doped phosphors for optical thermometry applications.
{"title":"Correlation between optical thermometry and Judd–Ofelt parameters in Er3+-doped perovskite oxides","authors":"C.Y. Lee, J.H. Han, Y.S. Lee","doi":"10.1016/j.cap.2025.09.025","DOIUrl":"10.1016/j.cap.2025.09.025","url":null,"abstract":"<div><div>We investigate the optical thermometric performance of Er<sup>3+</sup>-doped perovskite oxides with thermally coupled levels (TCLs). We obtain their optical thermometric parameters, such as their fluorescence intensity ratio and temperature sensitivity, from upconversion luminescence spectra under 980 nm excitation over a wide temperature range. Subsequently, we systematically compare these experimentally determined parameters with theoretical predictions for a TCL system, in addition to parameters derived from Judd–Ofelt (J–O) analysis, which is a well-established theoretical framework that describes the radiative transitions and intensities of rare-earth (RE) ions. A close correspondence between the experimental and theoretical results is achieved when the temperature-dependent variation of the J–O parameters and the TCL gap is considered. Our findings provide valuable insights into the roles of host-lattice effects, local crystal field variations, and defect-related phenomena in governing the thermal response of RE ion-doped phosphors for optical thermometry applications.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"80 ","pages":"Pages 265-272"},"PeriodicalIF":3.1,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145226938","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 : 2025-10-02DOI: 10.1016/j.cap.2025.10.003
Ibrar Ahmad , Syeeda Nida Alim , Khizar Hayat , Abdullah Shah , Sabir Shah , Said Karim Shah
This study explores the impact of active layer (AL) thickness, annealing temperatures(ATs), and interfacial materials on the performance of polymer solar cells (PSCs) based on P3HT: PCBM. AL thickness was tuned by varying spin speeds (1000–5000 rpm), with devices D1K and D4K achieving PCEs of 2.37 % and 2.17 % after thermal annealing at 130 °C. Increasing the AT to 180 °C further enhanced device efficiency. The influence of interfacial layers LiF and Ca on PSC performance and thermal stability was also investigated. Ca/Al-based devices outperformed others at lower temperatures but degraded at higher temperatures, while LiF/Al-based devices showed reduced PCE beyond ∼110 °C. To complement experiments, simulations using drift-diffusion, exciton-diffusion, and transfer-matrix models(TMM) were performed. These provided insights into photon distribution, absorption, and carrier generation, supporting the experimental outcomes. The study offers a comprehensive understanding of the interplay between device architecture and thermal treatment in optimizing PSC performance.
{"title":"Experimental and computational insights into optimizing polymer solar cell operational parameters","authors":"Ibrar Ahmad , Syeeda Nida Alim , Khizar Hayat , Abdullah Shah , Sabir Shah , Said Karim Shah","doi":"10.1016/j.cap.2025.10.003","DOIUrl":"10.1016/j.cap.2025.10.003","url":null,"abstract":"<div><div>This study explores the impact of active layer (AL) thickness, annealing temperatures(ATs), and interfacial materials on the performance of polymer solar cells (PSCs) based on P3HT: PCBM. AL thickness was tuned by varying spin speeds (1000–5000 rpm), with devices D1K and D4K achieving PCEs of 2.37 % and 2.17 % after thermal annealing at 130 °C. Increasing the AT to 180 °C further enhanced device efficiency. The influence of interfacial layers LiF and Ca on PSC performance and thermal stability was also investigated. Ca/Al-based devices outperformed others at lower temperatures but degraded at higher temperatures, while LiF/Al-based devices showed reduced PCE beyond ∼110 °C. To complement experiments, simulations using drift-diffusion, exciton-diffusion, and transfer-matrix models(TMM) were performed. These provided insights into photon distribution, absorption, and carrier generation, supporting the experimental outcomes. The study offers a comprehensive understanding of the interplay between device architecture and thermal treatment in optimizing PSC performance.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"80 ","pages":"Pages 291-299"},"PeriodicalIF":3.1,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145262496","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 : 2025-10-02DOI: 10.1016/j.cap.2025.10.001
Zhiyong Chen , Mengsi Liu , Shubo Cheng , Junqiao Wang , Yougen Yi , Boxun Li , Chaojun Tang , Fan Gao
The tunable terahertz perfect absorber based on a bilayer graphene metamaterial achieves breakthrough performance through an innovative design that combines a square array-box composite resonant cavity unit structure with dynamic Fermi level control. By adjusting the graphene Fermi level (0–0.5 eV), the absorption peak can dynamically switch from a single wide peak to a double-peak U-shaped depression, covering a tuning range of 3.99–8.91 THz. After optimization, the average absorption rate in the target frequency band reaches 97 %. This structure, through the synergistic mechanism of localized field enhancement and impedance matching, achieves the first active reconstruction of the absorption peak shape within a wide bandwidth (from a wide peak to a U-shaped peak), providing a new solution for terahertz stealth communication and high-sensitivity sensing.
{"title":"Bilayer graphene metasurface with dynamically reconfigurable terahertz perfect absorption","authors":"Zhiyong Chen , Mengsi Liu , Shubo Cheng , Junqiao Wang , Yougen Yi , Boxun Li , Chaojun Tang , Fan Gao","doi":"10.1016/j.cap.2025.10.001","DOIUrl":"10.1016/j.cap.2025.10.001","url":null,"abstract":"<div><div>The tunable terahertz perfect absorber based on a bilayer graphene metamaterial achieves breakthrough performance through an innovative design that combines a square array-box composite resonant cavity unit structure with dynamic Fermi level control. By adjusting the graphene Fermi level (0–0.5 eV), the absorption peak can dynamically switch from a single wide peak to a double-peak U-shaped depression, covering a tuning range of 3.99–8.91 THz. After optimization, the average absorption rate in the target frequency band reaches 97 %. This structure, through the synergistic mechanism of localized field enhancement and impedance matching, achieves the first active reconstruction of the absorption peak shape within a wide bandwidth (from a wide peak to a U-shaped peak), providing a new solution for terahertz stealth communication and high-sensitivity sensing.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"80 ","pages":"Pages 282-290"},"PeriodicalIF":3.1,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145262495","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 : 2025-10-01DOI: 10.1016/j.cap.2025.09.028
Muhammad Arif , Donghun Han , Seunghun Cha , Changsun Pak , Young-Kwang Kim , Sang Woo Kim , Bo Wha Lee , Muhammad Awais , Dongwhi Choi , Jong-Soo Rhyee
Soft magnetic composites are essential to power electronics technologies, including transformers, motors, and generators. However, as electronic devices advance, SMCs should have excellent soft magnetic properties, such as high permeability, high saturation magnetization, and reduced core loss at high frequencies. In this study, we found exceptionally high soft magnetic properties for Co nanopowder distribution in Fe3O4-coated Fe SMCs prepared via the hot-pressing technique. Incorporating Co nano-powders leads to a notable increase in density, with the most compact structure observed in the sample containing the highest Co concentration. Electrical resistivity increases to 55.54 mΩ cm for a sample containing 1 wt% Co nanopowder, compared to 15 mΩ cm for a pristine sample. The SMCs exhibit excellent soft magnetic properties, with high saturation magnetization (Ms ∼216 emu/g), high permeability (μe∼237.42) (144 % higher than the undoped sample), high DC bias performance (71.45 % at 100 kOe), and reduced core loss (Pcv, Ph, and Pe), compared to the other state-of-the-art samples. It indicates that Fe/Fe3O4-Co SMCs are highly promising for miniaturization and high-energy efficiency of electronic components.
{"title":"Enhancement of soft magnetic properties in surface-oxidized Fe/Fe3O4 composites via Co-nanoparticle doping and hot pressing","authors":"Muhammad Arif , Donghun Han , Seunghun Cha , Changsun Pak , Young-Kwang Kim , Sang Woo Kim , Bo Wha Lee , Muhammad Awais , Dongwhi Choi , Jong-Soo Rhyee","doi":"10.1016/j.cap.2025.09.028","DOIUrl":"10.1016/j.cap.2025.09.028","url":null,"abstract":"<div><div>Soft magnetic composites are essential to power electronics technologies, including transformers, motors, and generators. However, as electronic devices advance, SMCs should have excellent soft magnetic properties, such as high permeability, high saturation magnetization, and reduced core loss at high frequencies. In this study, we found exceptionally high soft magnetic properties for Co nanopowder distribution in Fe<sub>3</sub>O<sub>4</sub>-coated Fe SMCs prepared via the hot-pressing technique. Incorporating Co nano-powders leads to a notable increase in density, with the most compact structure observed in the sample containing the highest Co concentration. Electrical resistivity increases to 55.54 mΩ cm for a sample containing 1 wt% Co nanopowder, compared to 15 mΩ cm for a pristine sample. The SMCs exhibit excellent soft magnetic properties, with high saturation magnetization (<em>M</em><sub>s</sub> ∼216 emu/g), high permeability (<em>μ</em><sub>e</sub>∼237.42) (144 % higher than the undoped sample), high DC bias performance (71.45 % at 100 kOe), and reduced core loss (<em>P</em><sub>cv</sub>, <em>P</em><sub>h</sub>, and <em>P</em><sub>e</sub>), compared to the other state-of-the-art samples. It indicates that Fe/Fe<sub>3</sub>O<sub>4</sub>-Co SMCs are highly promising for miniaturization and high-energy efficiency of electronic components.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"80 ","pages":"Pages 256-264"},"PeriodicalIF":3.1,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145226828","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.2025.09.026
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}
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