Pub Date : 2025-04-22DOI: 10.1016/j.jallcom.2025.180569
H.T. Zhang, Q. Wang, Z.R. Zhang, X.J. Liu, D. Ding, L. Xia
Binary NdxNi100-x (x = 60, 65, 70, 73, 75) metallic glass (MG) ribbons were successfully produced in the present work, and their glass formability (GFA), Curie temperature (Tc) and magnetocaloric properties were studied systematically. The mechanisms for the dependence of Tc on the interactions between Nd-Ni atoms, and the origin of coercivity at low temperature, were revealed with the help of first-principles calculation and Monte Carlo simulations. The outcomes are valuable for intensively understanding the interactions between rare earth (RE) and transition metal (TM) atoms, and their influence on the magnetic properties of the RE-TM MGs.
{"title":"Investigation on the glass forming ability, magnetic properties of Nd-Ni binary metallic glasses and the mechanism involved","authors":"H.T. Zhang, Q. Wang, Z.R. Zhang, X.J. Liu, D. Ding, L. Xia","doi":"10.1016/j.jallcom.2025.180569","DOIUrl":"10.1016/j.jallcom.2025.180569","url":null,"abstract":"<div><div>Binary Nd<sub>x</sub>Ni<sub>100-x</sub> (x = 60, 65, 70, 73, 75) metallic glass (MG) ribbons were successfully produced in the present work, and their glass formability (GFA), Curie temperature (<em>T</em><sub><em>c</em></sub>) and magnetocaloric properties were studied systematically. The mechanisms for the dependence of <em>T</em><sub><em>c</em></sub> on the interactions between Nd-Ni atoms, and the origin of coercivity at low temperature, were revealed with the help of first-principles calculation and Monte Carlo simulations. The outcomes are valuable for intensively understanding the interactions between rare earth (RE) and transition metal (TM) atoms, and their influence on the magnetic properties of the RE-TM MGs.</div></div>","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"1027 ","pages":"Article 180569"},"PeriodicalIF":5.8,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143857952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
High saturation magnetization is a major issue with magnetic high entropy alloys (HEAs) which prevents these materials from being used for industrial applications. In the present study, Co35Cu5Fe10Ni30Ti20 HEA was synthesized through mechanical alloying and optimized for high saturation magnetization (Ms), low coercivity (Hc), and high electrical resistivity with excellent corrosion resistance through the annealing at different temperatures and for different durations. The as-synthesized HEA possessed the fcc phase, and the values of Ms and Hc were found to be 85 emu/g and 28 Oe, respectively. The synthesized HEA samples were annealed at different temperatures, i.e. 300°C, 500°C, 700°C and 900°C for 2 hr. All the annealed HEA samples except 500°C annealed HEA maintained initial phase identity. For 500°C annealed HEA, an additional bcc solid solution with the as-synthesized fcc phase was appeared. The value of Ms significantly increased with the annealing at different temperatures. Furthermore, we investigated the effect of long-duration annealing on the magnetic properties of the synthesized HEA. The high value of Ms and low value of Hc is obtained, i.e., Ms ∼ 118 emu/g & Hc ∼ 9 Oe and Ms ∼ 122 emu/g & Hc ∼ 2 Oe for 700°C 10 hr and 20 hr annealed HEAs, respectively. We also measured the electrical resistivity and corrosion resistance for 700°C, 20 hr annealed HEA sample and found them to be 319 µΩ and 0.247 mm/year, respectively. Thus, the optimized HEA sample, i.e., 700°C, 20 hr annealed HEA, exhibited an excellent combination of multiple functional properties (i.e., magnetic, electrical, and corrosion properties) that can potentially be used for soft magnetic industrial applications. The optimization through different temperatures and durations of annealing and a detailed insight into the work also opens up new paths for the researchers to design advanced HEAs that can fulfil the future demands of modern industries.
{"title":"Excellent soft magnetic with high electrical and corrosion resistance properties of Co35Cu5Fe10Ni30Ti20 high entropy alloy","authors":"Shashi Kant Mohapatra , Priyanka Kumari , R.J. Choudhary , Archana Lakhani , Rohit R. Shahi","doi":"10.1016/j.jallcom.2025.180584","DOIUrl":"10.1016/j.jallcom.2025.180584","url":null,"abstract":"<div><div>High saturation magnetization is a major issue with magnetic high entropy alloys (HEAs) which prevents these materials from being used for industrial applications. In the present study, Co<sub>35</sub>Cu<sub>5</sub>Fe<sub>10</sub>Ni<sub>30</sub>Ti<sub>20</sub> HEA was synthesized through mechanical alloying and optimized for high saturation magnetization (<em>M</em>s), low coercivity (<em>H</em>c), and high electrical resistivity with excellent corrosion resistance through the annealing at different temperatures and for different durations. The as-synthesized HEA possessed the fcc phase, and the values of <em>M</em>s and <em>H</em>c were found to be 85 emu/g and 28 Oe, respectively. The synthesized HEA samples were annealed at different temperatures, i.e. 300°C, 500°C, 700°C and 900°C for 2 hr. All the annealed HEA samples except 500°C annealed HEA maintained initial phase identity. For 500°C annealed HEA, an additional bcc solid solution with the as-synthesized fcc phase was appeared. The value of <em>M</em>s significantly increased with the annealing at different temperatures. Furthermore, we investigated the effect of long-duration annealing on the magnetic properties of the synthesized HEA. The high value of <em>M</em>s and low value of <em>H</em>c is obtained, i.e., <em>M</em>s ∼ 118 emu/g & <em>H</em>c ∼ 9 Oe and <em>M</em>s ∼ 122 emu/g & <em>H</em>c ∼ 2 Oe for 700°C 10 hr and 20 hr annealed HEAs, respectively. We also measured the electrical resistivity and corrosion resistance for 700°C, 20 hr annealed HEA sample and found them to be 319 µΩ and 0.247 mm/year, respectively. Thus, the optimized HEA sample, i.e., 700°C, 20 hr annealed HEA, exhibited an excellent combination of multiple functional properties (i.e., magnetic, electrical, and corrosion properties) that can potentially be used for soft magnetic industrial applications. The optimization through different temperatures and durations of annealing and a detailed insight into the work also opens up new paths for the researchers to design advanced HEAs that can fulfil the future demands of modern industries.</div></div>","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"1027 ","pages":"Article 180584"},"PeriodicalIF":5.8,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143862716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-22DOI: 10.1016/j.jallcom.2025.180566
ZhanMing Yin , Tong Liu , Yu Yang , Rongli Sang , Zhanshen Zheng , Jixiang Duan , Yuanliang Li
Bismuth-based materials, known for their unique layered structure, have emerged as promising candidates for semiconductor photocatalysts. However, their practical application is often hindered by wide band gaps and limited visible light absorption, leading to low photocatalytic efficiency. To address these challenges, we developed a novel CaBi4Ti4O15/BiOI (CBTO/BOI) heterojunction catalyst, leveraging the synergistic effects of piezoelectricity and photocatalysis. The heterogeneous structure of CBTO/BOI, combined with the intrinsic polarization effect of CBTO, significantly enhances the separation of electron-hole pairs, providing a robust driving force for catalytic degradation. This multi-modal catalytic process efficiently harnesses both solar and mechanical energy, enabling rapid carrier separation and migration. Under simultaneous light and ultrasonic irradiation, the CBTO/BOI catalyst achieved an exceptional 98.36 % degradation of Rhodamine B (RhB) within 16 min, with a remarkable rate constant of k = 0.2298 min−1, surpassing most reported piezoelectric photocatalysts. This study not only presents a highly efficient and environmentally friendly approach for pollutant degradation through multi-modal energy harvesting but also opens new avenues for the design of advanced photocatalysts for sustainable environmental remediation.
{"title":"Multi-modal energy harvesting for efficient piezoelectric photocatalytic pollutant degradation using CaBi4Ti4O15/BiOI heterojunctions with excellent piezoelectric properties","authors":"ZhanMing Yin , Tong Liu , Yu Yang , Rongli Sang , Zhanshen Zheng , Jixiang Duan , Yuanliang Li","doi":"10.1016/j.jallcom.2025.180566","DOIUrl":"10.1016/j.jallcom.2025.180566","url":null,"abstract":"<div><div>Bismuth-based materials, known for their unique layered structure, have emerged as promising candidates for semiconductor photocatalysts. However, their practical application is often hindered by wide band gaps and limited visible light absorption, leading to low photocatalytic efficiency. To address these challenges, we developed a novel CaBi<sub>4</sub>Ti<sub>4</sub>O<sub>15</sub>/BiOI (CBTO/BOI) heterojunction catalyst, leveraging the synergistic effects of piezoelectricity and photocatalysis. The heterogeneous structure of CBTO/BOI, combined with the intrinsic polarization effect of CBTO, significantly enhances the separation of electron-hole pairs, providing a robust driving force for catalytic degradation. This multi-modal catalytic process efficiently harnesses both solar and mechanical energy, enabling rapid carrier separation and migration. Under simultaneous light and ultrasonic irradiation, the CBTO/BOI catalyst achieved an exceptional 98.36 % degradation of Rhodamine B (RhB) within 16 min, with a remarkable rate constant of <em>k</em> = 0.2298 min<sup>−1</sup>, surpassing most reported piezoelectric photocatalysts. This study not only presents a highly efficient and environmentally friendly approach for pollutant degradation through multi-modal energy harvesting but also opens new avenues for the design of advanced photocatalysts for sustainable environmental remediation.</div></div>","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"1027 ","pages":"Article 180566"},"PeriodicalIF":5.8,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143857953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-22DOI: 10.1016/j.jallcom.2025.180582
Gemeng Huang, Ziyou Wang, Chen Yang, Ming Ma, Song Xia, Shiji Fan, Zhenrong Li
A total of 11 GaN crystals measuring 10 × 13 mm2 were successfully grown simultaneously on vertical multiple MOCVD-GaN thin film seeds utilizing the Na-flux liquid-phase epitaxy method. All the crystals are highly consistent and evident in their uniform cellular morphology. The top-to-bottom variation in sample thickness is related to their location in the crucible. Samples situated at the most marginal region of the solution show a consistent monotonic increase in thickness from the bottom to the top. In contrast, those located in the sub-marginal regions demonstrate a significant decrease in thickness along the longitudinal axis. Conversely, samples found in the more central regions maintain relatively uniform thickness profiles from the bottom to the apex, with the most central specimen notably displaying perfect uniformity in thickness across the entire height. The bottom-up variation of sample thickness is consistent with the bottom-up trend of the longitudinal nitrogen concentration near the surface of the seed crystals in solution. The thickness variation from top to bottom in all samples is at most 160μm, which is approximately 8μm less per millimeter compared to the previous Na-flux growth of vertically placed single GaN crystals, indicating a significant improvement in thickness uniformity. Numerical optimization reveals that doubling the solution height could improve the uniformity of longitudinal nitrogen concentration adjacent to the seed crystal surfaces. The successful growth of multiple GaN crystals using this method effectively addresses the issue of low crystal growth efficiency and lays a solid foundation for the large-scale production of GaN crystals.
{"title":"Simultaneous Growth of Multiple GaN Crystals and Numerical Optimization in the Na-flux Liquid Phase Method","authors":"Gemeng Huang, Ziyou Wang, Chen Yang, Ming Ma, Song Xia, Shiji Fan, Zhenrong Li","doi":"10.1016/j.jallcom.2025.180582","DOIUrl":"https://doi.org/10.1016/j.jallcom.2025.180582","url":null,"abstract":"A total of 11 GaN crystals measuring 10 × 13 mm<sup>2</sup> were successfully grown simultaneously on vertical multiple MOCVD-GaN thin film seeds utilizing the Na-flux liquid-phase epitaxy method. All the crystals are highly consistent and evident in their uniform cellular morphology. The top-to-bottom variation in sample thickness is related to their location in the crucible. Samples situated at the most marginal region of the solution show a consistent monotonic increase in thickness from the bottom to the top. In contrast, those located in the sub-marginal regions demonstrate a significant decrease in thickness along the longitudinal axis. Conversely, samples found in the more central regions maintain relatively uniform thickness profiles from the bottom to the apex, with the most central specimen notably displaying perfect uniformity in thickness across the entire height. The bottom-up variation of sample thickness is consistent with the bottom-up trend of the longitudinal nitrogen concentration near the surface of the seed crystals in solution. The thickness variation from top to bottom in all samples is at most 160μm, which is approximately 8μm less per millimeter compared to the previous Na-flux growth of vertically placed single GaN crystals, indicating a significant improvement in thickness uniformity. Numerical optimization reveals that doubling the solution height could improve the uniformity of longitudinal nitrogen concentration adjacent to the seed crystal surfaces. The successful growth of multiple GaN crystals using this method effectively addresses the issue of low crystal growth efficiency and lays a solid foundation for the large-scale production of GaN crystals.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"19 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143862668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-22DOI: 10.1016/j.jallcom.2025.180543
Fangyin Lu , Qingshuang Ma , Enyu Liu , Ruibo Wei , Jing Bai , Qiuzhi Gao , Jian Qi
In recent years, considerable attention has been devoted to implementing additive manufacturing (AM) techniques in the fabrication of Ti-6Al-4V alloy. During manufacturing, metallic powders are melted and rapidly solidified utilizing laser or electron beam sources, experiencing intricate thermal cycles that confer unique microstructural characteristics and exceptional performance attributes upon the titanium alloys. This paper presents an exhaustive review of the utilization of AM technologies in the production of Ti-6Al-4V alloy, with particular emphasis placed on this alloy itself. Specifically, the advantages and limitations of two prominent AM methodologies—laser powder bed fusion (LPBF) and directed energy deposition (DED)—are critically evaluated. Moreover, an in-depth analysis of pore defect formation mechanisms is provided, elucidating their consequential influence on the mechanical integrity of AM-processed Ti-6Al-4V alloy. Additionally, this review summarizes and contrasts the mechanical properties, hardness, wear resistance, corrosion resistance, and oxidation resistance exhibited by Ti-6Al-4V alloy fabricated through various AM technologies, as well as methodologies implemented to enhance these characteristics. In aggregate, this review aims to provide a robust theoretical framework and pivotal insights essential for advancing the development of high-performance titanium alloys through the strategic deployment of AM technologies.
Additive manufacturing (AM) processes, such as DED and LPBF, involve melting metal powders with lasers or electron beams to produce unique microstructures and outstanding performance. This review summarizes the advantages and disadvantages, microstructure, pore defect formation mechanism, and their impact on performance of these 3 AM methods. At the same time, the mechanical properties, hardness, wear, corrosion, and oxidation resistance of Ti-6Al-4V alloy produced by AM are summarized, providing insights for the future development of high-performance titanium alloy manufacturing.
{"title":"Advancements in understanding the microstructure and properties of additive manufacturing Ti-6Al-4V alloy: A comprehensive review","authors":"Fangyin Lu , Qingshuang Ma , Enyu Liu , Ruibo Wei , Jing Bai , Qiuzhi Gao , Jian Qi","doi":"10.1016/j.jallcom.2025.180543","DOIUrl":"10.1016/j.jallcom.2025.180543","url":null,"abstract":"<div><div>In recent years, considerable attention has been devoted to implementing additive manufacturing (AM) techniques in the fabrication of Ti-6Al-4V alloy. During manufacturing, metallic powders are melted and rapidly solidified utilizing laser or electron beam sources, experiencing intricate thermal cycles that confer unique microstructural characteristics and exceptional performance attributes upon the titanium alloys. This paper presents an exhaustive review of the utilization of AM technologies in the production of Ti-6Al-4V alloy, with particular emphasis placed on this alloy itself. Specifically, the advantages and limitations of two prominent AM methodologies—laser powder bed fusion (LPBF) and directed energy deposition (DED)—are critically evaluated. Moreover, an in-depth analysis of pore defect formation mechanisms is provided, elucidating their consequential influence on the mechanical integrity of AM-processed Ti-6Al-4V alloy. Additionally, this review summarizes and contrasts the mechanical properties, hardness, wear resistance, corrosion resistance, and oxidation resistance exhibited by Ti-6Al-4V alloy fabricated through various AM technologies, as well as methodologies implemented to enhance these characteristics. In aggregate, this review aims to provide a robust theoretical framework and pivotal insights essential for advancing the development of high-performance titanium alloys through the strategic deployment of AM technologies.</div><div>Additive manufacturing (AM) processes, such as DED and LPBF, involve melting metal powders with lasers or electron beams to produce unique microstructures and outstanding performance. This review summarizes the advantages and disadvantages, microstructure, pore defect formation mechanism, and their impact on performance of these 3 AM methods. At the same time, the mechanical properties, hardness, wear, corrosion, and oxidation resistance of Ti-6Al-4V alloy produced by AM are summarized, providing insights for the future development of high-performance titanium alloy manufacturing.</div></div>","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"1027 ","pages":"Article 180543"},"PeriodicalIF":5.8,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143862715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-22DOI: 10.1016/j.jallcom.2025.180581
Francesco Stancari, Francesco Pattini, Francesco Mezzadri, Giulia Spaggiari, Stefano Rampino, Antonella Parisini, Maura Pavesi, Andrea Baraldi, Marzio Rancan, Lidia Armelao, Roberto Fornari
The Pulsed Electron Deposition (PED) technique was exploited to explore n-type doping of β-Ga2O3 thin films. Layers were deposited on (0001) sapphire at low-temperature (500°C), using homemade targets including variable amounts of Sn, Ge and Zr. The undoped films show a pure β-Ga2O3 phase with high crystallinity and an insulating nature, reporting resistivity values higher than 107 Ω cm. The introduction of Sn leads to the formation of films including both |- and β-Ga2O3, with an electrical resistivity of approximately 10⁵ Ω cm. The doping with Ge results in the formation of high-quality β-Ga2O3 layers, but with high resistivity (~106 Ω cm). Zr is identified as the most effective dopant, resulting in the formation of single-phase epitaxial β-Ga2O3 films with low resistivity (~5 Ω cm). The present study indicates the PED technique to be an effective method for the deposition of good quality epitaxial β-Ga2O3 films at low temperatures, allowing the simple exploration of doping without the need for complex or toxic precursors.
{"title":"Tetravalent Element Doping of β-Ga₂O₃ Films Grown by Pulsed Electron Deposition Technique","authors":"Francesco Stancari, Francesco Pattini, Francesco Mezzadri, Giulia Spaggiari, Stefano Rampino, Antonella Parisini, Maura Pavesi, Andrea Baraldi, Marzio Rancan, Lidia Armelao, Roberto Fornari","doi":"10.1016/j.jallcom.2025.180581","DOIUrl":"https://doi.org/10.1016/j.jallcom.2025.180581","url":null,"abstract":"The Pulsed Electron Deposition (PED) technique was exploited to explore n-type doping of β-Ga<sub>2</sub>O<sub>3</sub> thin films. Layers were deposited on (0001) sapphire at low-temperature (500°C), using homemade targets including variable amounts of Sn, Ge and Zr. The undoped films show a pure β-Ga<sub>2</sub>O<sub>3</sub> phase with high crystallinity and an insulating nature, reporting resistivity values higher than 10<sup>7</sup> Ω cm. The introduction of Sn leads to the formation of films including both |- and β-Ga<sub>2</sub>O<sub>3</sub>, with an electrical resistivity of approximately 10⁵ Ω cm. The doping with Ge results in the formation of high-quality β-Ga<sub>2</sub>O<sub>3</sub> layers, but with high resistivity (~10<sup>6</sup> Ω cm). Zr is identified as the most effective dopant, resulting in the formation of single-phase epitaxial β-Ga<sub>2</sub>O<sub>3</sub> films with low resistivity (~5 Ω cm). The present study indicates the PED technique to be an effective method for the deposition of good quality epitaxial β-Ga<sub>2</sub>O<sub>3</sub> films at low temperatures, allowing the simple exploration of doping without the need for complex or toxic precursors.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"19 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143862681","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-22DOI: 10.1016/j.jallcom.2025.180578
Lingxi Qiu , Yipeng An , Liyan Shang , Yawei Li , Cheng Gong , Junhao Chu , Zhigao Hu , Shi-Jing Gong
Two-dimensional (2D) Janus magnets exhibit a broad range of exotic physical phenomena, e.g. skyrmions and strong Rashba SOC, and become an important category of spintronic materials. Here, we design the Janus structure Cr2Ge2Te3Se3 based on the unipolar magnetic semiconductor (UMS) Cr2Ge2Te6, and find that Cr2Ge2Te3Se3 becomes a bipolar magnetic semiconductor (BMS), whose valence band maximum (VBM) and conduction band minimum (CBM) have opposite spin polarization. The transition from UMS Cr2Ge2Te6 to BMS Cr2Ge2Te3Se3 is achieved because the VBM is contributed by electronic states of the Se and Te atoms, which can be effectively modified by the mirror symmetry breaking. We then design a spin field-effect transistor (FET) based on Cr2Ge2Te3Se3, and demonstrate the half-metallic current tuned by the gate and bias voltages, through non-equilibrium Green’s function theory. Our investigation schemes a 2D BMS and simulates its application in spin-FET, which potentially contributes to the development of 2D spintronic materials and devices.
{"title":"Bipolar magnetic semiconductor of 2D Janus Cr2Ge2Te3Se3 and its application in spin-FET","authors":"Lingxi Qiu , Yipeng An , Liyan Shang , Yawei Li , Cheng Gong , Junhao Chu , Zhigao Hu , Shi-Jing Gong","doi":"10.1016/j.jallcom.2025.180578","DOIUrl":"10.1016/j.jallcom.2025.180578","url":null,"abstract":"<div><div>Two-dimensional (2D) Janus magnets exhibit a broad range of exotic physical phenomena, e.g. skyrmions and strong Rashba SOC, and become an important category of spintronic materials. Here, we design the Janus structure Cr<sub>2</sub>Ge<sub>2</sub>Te<sub>3</sub>Se<sub>3</sub> based on the unipolar magnetic semiconductor (UMS) Cr<sub>2</sub>Ge<sub>2</sub>Te<sub>6</sub>, and find that Cr<sub>2</sub>Ge<sub>2</sub>Te<sub>3</sub>Se<sub>3</sub> becomes a bipolar magnetic semiconductor (BMS), whose valence band maximum (VBM) and conduction band minimum (CBM) have opposite spin polarization. The transition from UMS Cr<sub>2</sub>Ge<sub>2</sub>Te<sub>6</sub> to BMS Cr<sub>2</sub>Ge<sub>2</sub>Te<sub>3</sub>Se<sub>3</sub> is achieved because the VBM is contributed by electronic states of the Se and Te atoms, which can be effectively modified by the mirror symmetry breaking. We then design a spin field-effect transistor (FET) based on Cr<sub>2</sub>Ge<sub>2</sub>Te<sub>3</sub>Se<sub>3</sub>, and demonstrate the half-metallic current tuned by the gate and bias voltages, through non-equilibrium Green’s function theory. Our investigation schemes a 2D BMS and simulates its application in spin-FET, which potentially contributes to the development of 2D spintronic materials and devices.</div></div>","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"1027 ","pages":"Article 180578"},"PeriodicalIF":5.8,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143862678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-21DOI: 10.1016/j.jallcom.2025.180535
Tian-En Shi, Xing Yang, Wen-Jie Li, Ze Li, Zi-Yuan Wang, Yi-Xin Zhang, Jing Feng, Zhen-Hua Ge
SnSe crystals have attracted considerable attention in thermoelectric due to their outstanding performance. However, the mechanical properties of crystals are poor and the synthesis of crystals is usually associated with complex processes. Polycrystalline SnSe materials are more advantageous for practical applications. Herein, a strategy of constructing multiple lattice defects by (Zr, Cl) co-doping is proposed, which is effective in realizing simultaneously optimized electrical and thermal transport properties. The multiscale-defects play the key roles in regulating thermoelectric properties: the foreign ions have entered into the lattice of matrix, causing the tuned carrier concentration, and the produced conductive precipitates along the grain boundaries benefit for maintaining the carrier mobility. In addition, multiscale lattice defects, such as pores, dislocations and precipitates, are favor of enhancing the phonon scattering for lowering lattice thermal conductivity. The STEM analysis and lattice thermal conductivity model calculations confirm the effects of various mechanisms on reducing the thermal conductivity in the (Zr, Cl) co-doped polycrystalline SnSe materials. Ultimately, a high ZT value of 1.42 is obtained at 773 K for the optimum specimen, and the average ZT within the temperature range of 573−773 K reaches 1.01. These results suggest that the strategy of (Zr, Cl) co-doping can simultaneously improve the thermoelectric performance in n-type SnSe materials, which might be worth promoting in other systems.
{"title":"Multiscale-defects Simultaneous Optimization of Thermoelectric Performance in the n-Type Polycrystalline SnSe via (Zr, Cl) Co-doping","authors":"Tian-En Shi, Xing Yang, Wen-Jie Li, Ze Li, Zi-Yuan Wang, Yi-Xin Zhang, Jing Feng, Zhen-Hua Ge","doi":"10.1016/j.jallcom.2025.180535","DOIUrl":"https://doi.org/10.1016/j.jallcom.2025.180535","url":null,"abstract":"SnSe crystals have attracted considerable attention in thermoelectric due to their outstanding performance. However, the mechanical properties of crystals are poor and the synthesis of crystals is usually associated with complex processes. Polycrystalline SnSe materials are more advantageous for practical applications. Herein, a strategy of constructing multiple lattice defects by (Zr, Cl) co-doping is proposed, which is effective in realizing simultaneously optimized electrical and thermal transport properties. The multiscale-defects play the key roles in regulating thermoelectric properties: the foreign ions have entered into the lattice of matrix, causing the tuned carrier concentration, and the produced conductive precipitates along the grain boundaries benefit for maintaining the carrier mobility. In addition, multiscale lattice defects, such as pores, dislocations and precipitates, are favor of enhancing the phonon scattering for lowering lattice thermal conductivity. The STEM analysis and lattice thermal conductivity model calculations confirm the effects of various mechanisms on reducing the thermal conductivity in the (Zr, Cl) co-doped polycrystalline SnSe materials. Ultimately, a high ZT value of 1.42 is obtained at 773<!-- --> <!-- -->K for the optimum specimen, and the average ZT within the temperature range of 573−773<!-- --> <!-- -->K reaches 1.01. These results suggest that the strategy of (Zr, Cl) co-doping can simultaneously improve the thermoelectric performance in n-type SnSe materials, which might be worth promoting in other systems.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"31 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143857975","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-21DOI: 10.1016/j.jallcom.2025.180556
Lei Yang , Yiting Dong , Xiaoxian Tian , Jun Yin , Qingwan Wang , Wanxin Wu , Ying Yang , Lulu Tang , Xueqin Yuan
Transition metal oxides have shown great potential to replace the noble metal-based catalysts in electrochemical oxygen evolution reaction (OER) process. High entropy oxides (HEOs) containing five or more equimolar cations in a single phase are promising electrocatalysts for enhancing OER efficiency due to their tunable electrochemical properties. Moreover, one dimensional (1D) structure materials with larger surface area can decrease the diffusion length for reactants and products, which is beneficial to the kinetics and mass transport of OER process. In this paper, a series of 1D AWO4 and A2O3 structured HEO nanowires (NWs) which are composed of six or five different transition metal elements are synthesized via a simple electrospinning strategy followed by heat treatment in air. Benefitting from the 1D structure and the synergetic effects between multiple metal cations, the as-synthesized AWO4 and A2O3 structured HEO NWs are proved to exhibit the superior OER performance than that of HEO nanoparticles (NPs), medium entropy oxides (MEOs) NWs and single component metal oxide NWs. The AWO4 (A2O3) structured HEO NWs show excellent catalytic activity with the overpotential of 296–451 mV (348–487 mV) at the current density of 10 mA/cm2 and the Tafel slope of 58–75 mV/dec (61–72 mV/dec). Our work enriches the choice of advanced materials for OER catalysts and provides a new idea to design and prepare the nanostructured HEOs in the field of new energy resources.
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