The design of composite powders for exploiting the multifunctionality of metallic nanocomposites via laser additive manufacturing (AM) is challenging. Conventional ball-milling processes are prone to cause uncontrollable powder morphology and reduced flowability, while recently developed nanodecoration technologies are limited by complicated processing and impurity inclusion. Herein, a facile and scalable approach was developed using ultrafine bubble (UFB)-assisted heteroagglomeration to fabricate high-concentration, impurity-free nanoceramic/metal composite powders. Individual ZrO2 or Al2O3 nanoparticles up to ~10 wt% were homogeneously decorated on the surface of Ti-6Al-4V powders through the bridging effect of the negatively charged UFBs, leading to enhanced flowability and laser absorptivity. The nanoceramics were completely decomposed and dissolved into the matrix upon laser irradiation; therefore, a unique Ti nanocomposite exhibiting both high strength and ductility was obtained. Our work provides new insights into the application of UFBs and the fabrication of multifunctional AM components. Researchers have developed a novel ultrafine bubble-assisted heteroagglomeration (UFBH) method to economically fabricate high-concentration, impurity-free nanoceramic/metal powders for additive manufacturing. Using negatively charged UFBs, they successfully promoted the uniform decoration of positively charged nanoceramic particles on metal powder surfaces via electrostatic self-assembly. The resulting 1 wt% ZrO2/Ti64 component fabricated by laser powder bed fusion (L-PBF) exhibited a unique combination of high tensile strength and high ductility due to significant solid solution strengthening and grain refinement. This study introduces a facile and scalable approach using UFBH and laser AM processes to design multifunctional metallic components, paving the way for the production of novel composite powders and high-performance AM components. A facile and scalable approach was developed using ultrafine bubble (UFB)-assisted heteroagglomeration to fabricate high-concentration, impurity-free nanoceramic/metal composite powders for additive manufacturin. Individual ZrO2 or Al2O3 nanoparticles up to ~10 wt% were homogeneously decorated on the surface of Ti-6Al-4V powders through the bridging effect of the negatively charged UFBs. The nanoceramics were completely decomposed and dissolved into the matrix upon laser irradiation; therefore, a unique Ti nanocomposite exhibiting both high strength and ductility was obtained.
{"title":"Ultrafine-bubble-water-promoted nanoceramic decoration of metal powders for additive manufacturing","authors":"Mingqi Dong, Weiwei Zhou, Suxia Guo, Naoyuki Nomura","doi":"10.1038/s41427-023-00494-9","DOIUrl":"10.1038/s41427-023-00494-9","url":null,"abstract":"The design of composite powders for exploiting the multifunctionality of metallic nanocomposites via laser additive manufacturing (AM) is challenging. Conventional ball-milling processes are prone to cause uncontrollable powder morphology and reduced flowability, while recently developed nanodecoration technologies are limited by complicated processing and impurity inclusion. Herein, a facile and scalable approach was developed using ultrafine bubble (UFB)-assisted heteroagglomeration to fabricate high-concentration, impurity-free nanoceramic/metal composite powders. Individual ZrO2 or Al2O3 nanoparticles up to ~10 wt% were homogeneously decorated on the surface of Ti-6Al-4V powders through the bridging effect of the negatively charged UFBs, leading to enhanced flowability and laser absorptivity. The nanoceramics were completely decomposed and dissolved into the matrix upon laser irradiation; therefore, a unique Ti nanocomposite exhibiting both high strength and ductility was obtained. Our work provides new insights into the application of UFBs and the fabrication of multifunctional AM components. Researchers have developed a novel ultrafine bubble-assisted heteroagglomeration (UFBH) method to economically fabricate high-concentration, impurity-free nanoceramic/metal powders for additive manufacturing. Using negatively charged UFBs, they successfully promoted the uniform decoration of positively charged nanoceramic particles on metal powder surfaces via electrostatic self-assembly. The resulting 1 wt% ZrO2/Ti64 component fabricated by laser powder bed fusion (L-PBF) exhibited a unique combination of high tensile strength and high ductility due to significant solid solution strengthening and grain refinement. This study introduces a facile and scalable approach using UFBH and laser AM processes to design multifunctional metallic components, paving the way for the production of novel composite powders and high-performance AM components. A facile and scalable approach was developed using ultrafine bubble (UFB)-assisted heteroagglomeration to fabricate high-concentration, impurity-free nanoceramic/metal composite powders for additive manufacturin. Individual ZrO2 or Al2O3 nanoparticles up to ~10 wt% were homogeneously decorated on the surface of Ti-6Al-4V powders through the bridging effect of the negatively charged UFBs. The nanoceramics were completely decomposed and dissolved into the matrix upon laser irradiation; therefore, a unique Ti nanocomposite exhibiting both high strength and ductility was obtained.","PeriodicalId":19382,"journal":{"name":"Npg Asia Materials","volume":"15 1","pages":"1-8"},"PeriodicalIF":8.6,"publicationDate":"2023-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41427-023-00494-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46540504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-25DOI: 10.1038/s41427-023-00492-x
Wenqiang Zhang, Jingzhuo Zhou, Yanwen Jia, Juzheng Chen, Yiru Pu, Rong Fan, Fanling Meng, Qi Ge, Yang Lu
Active metamaterials with shapes or mechanical properties that can be controlled remotely are promising candidates for soft robots, flexible electronics, and medical applications. However, current active metamaterials often have long response times and short ranges of linear working strains. Here, we demonstrate magnetoactive microlattice metamaterials constructed from 3D-printed, ultra-flexible polymer shells filled with magnetorheological (MR) fluid. Under compressive stress, the magnetorheological fluid develops hydrostatic pressure, allowing for a linear compression strain of more than 30% without buckling. We further show that under a relatively low magnetic field strength (approximately 60 mT), the microlattices can become approximately 200% stiffer than those in a relaxed state, and the energy absorption increases ~16 times. Furthermore, our microlattices showed an ultra-low response time with “field on” and “field off” times of ~200 ms and ~50 ms, respectively. The ability to continuously tune the mechanical properties of these materials in real time make it possible to modulate stress‒strain behavior on demand. Our study provides a new route toward large-scale, highly tunable, and remotely controllable metamaterials with potential applications in wearable exoskeletons, tactile sensors, and medical supports. A liquid–solid dual-phase magnetoactive microlattice metamaterial composed of flexible 3D-printed polymer shell and magnetorheological (MR) fluid has been designed and fabricated. The MR fluid-filled magnetoactive microlattices demonstrated remarkable recoverability (~50%) and be substantially stiffened in the presence of a magnetic field, with an ~200% increment in stiffness at 60 mT. Based on specific applications, the mechanical properties of this magnetoactive microlattice metamaterial can be modulated on demand, leading to certain programmable stress-strain behavior.
{"title":"Magnetoactive microlattice metamaterials with highly tunable stiffness and fast response rate","authors":"Wenqiang Zhang, Jingzhuo Zhou, Yanwen Jia, Juzheng Chen, Yiru Pu, Rong Fan, Fanling Meng, Qi Ge, Yang Lu","doi":"10.1038/s41427-023-00492-x","DOIUrl":"10.1038/s41427-023-00492-x","url":null,"abstract":"Active metamaterials with shapes or mechanical properties that can be controlled remotely are promising candidates for soft robots, flexible electronics, and medical applications. However, current active metamaterials often have long response times and short ranges of linear working strains. Here, we demonstrate magnetoactive microlattice metamaterials constructed from 3D-printed, ultra-flexible polymer shells filled with magnetorheological (MR) fluid. Under compressive stress, the magnetorheological fluid develops hydrostatic pressure, allowing for a linear compression strain of more than 30% without buckling. We further show that under a relatively low magnetic field strength (approximately 60 mT), the microlattices can become approximately 200% stiffer than those in a relaxed state, and the energy absorption increases ~16 times. Furthermore, our microlattices showed an ultra-low response time with “field on” and “field off” times of ~200 ms and ~50 ms, respectively. The ability to continuously tune the mechanical properties of these materials in real time make it possible to modulate stress‒strain behavior on demand. Our study provides a new route toward large-scale, highly tunable, and remotely controllable metamaterials with potential applications in wearable exoskeletons, tactile sensors, and medical supports. A liquid–solid dual-phase magnetoactive microlattice metamaterial composed of flexible 3D-printed polymer shell and magnetorheological (MR) fluid has been designed and fabricated. The MR fluid-filled magnetoactive microlattices demonstrated remarkable recoverability (~50%) and be substantially stiffened in the presence of a magnetic field, with an ~200% increment in stiffness at 60 mT. Based on specific applications, the mechanical properties of this magnetoactive microlattice metamaterial can be modulated on demand, leading to certain programmable stress-strain behavior.","PeriodicalId":19382,"journal":{"name":"Npg Asia Materials","volume":"15 1","pages":"1-8"},"PeriodicalIF":8.6,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41427-023-00492-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46566773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-18DOI: 10.1038/s41427-023-00491-y
Zhixuan Wen, Teng Zhou, Qian Xu, Weipeng Chen, Weiwen Xin, Xiang-Yu Kong, Lei Jiang
Shellfish with rigid shells prevent damage to their delicate internal cores, and their soft bonding muscles drive the opening and closing of the shells. This synergism of rigid and soft materials provides shellfish with unique environmental adaptation. Inspired by the structural characteristics of mussels, a riveting layer was introduced into hydrogel-plastic hybrids for bonding hydrogel networks and plastic substrates. The bonding strength of the hydrogel on the polypropylene (PP) substrate was approximately 1.52 MPa, and the interface toughness reached 1450 J m−2. Furthermore, the integration of plastics and microscale hydrogels, as well as abscised or prefabricated hydrogels, could also be fabricated through the same process. By using this strategy, a hydrogel-plastic hybrid-based device with temperature responsiveness and scratch resistance was fabricated and could mimic the basic activities of mussels. This work improves the functional materials used in programmable engineering systems and could facilitate the construction of intelligent robots. Drawing inspiration from the structural attributes of mussels, we have introduced a riveting layer into our hydrogel-plastic hybrids, facilitating robust bonding between hydrogel networks and plastic substrates. This work underscores the immense potential and advantages that this integration of hydrogels and plastics holds, especially in the development of intelligent robotics.
{"title":"Functional hydrogel-plastic hybrids inspired by the structural characteristics of mussels","authors":"Zhixuan Wen, Teng Zhou, Qian Xu, Weipeng Chen, Weiwen Xin, Xiang-Yu Kong, Lei Jiang","doi":"10.1038/s41427-023-00491-y","DOIUrl":"10.1038/s41427-023-00491-y","url":null,"abstract":"Shellfish with rigid shells prevent damage to their delicate internal cores, and their soft bonding muscles drive the opening and closing of the shells. This synergism of rigid and soft materials provides shellfish with unique environmental adaptation. Inspired by the structural characteristics of mussels, a riveting layer was introduced into hydrogel-plastic hybrids for bonding hydrogel networks and plastic substrates. The bonding strength of the hydrogel on the polypropylene (PP) substrate was approximately 1.52 MPa, and the interface toughness reached 1450 J m−2. Furthermore, the integration of plastics and microscale hydrogels, as well as abscised or prefabricated hydrogels, could also be fabricated through the same process. By using this strategy, a hydrogel-plastic hybrid-based device with temperature responsiveness and scratch resistance was fabricated and could mimic the basic activities of mussels. This work improves the functional materials used in programmable engineering systems and could facilitate the construction of intelligent robots. Drawing inspiration from the structural attributes of mussels, we have introduced a riveting layer into our hydrogel-plastic hybrids, facilitating robust bonding between hydrogel networks and plastic substrates. This work underscores the immense potential and advantages that this integration of hydrogels and plastics holds, especially in the development of intelligent robotics.","PeriodicalId":19382,"journal":{"name":"Npg Asia Materials","volume":"15 1","pages":"1-8"},"PeriodicalIF":8.6,"publicationDate":"2023-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41427-023-00491-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48700172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Manipulating nanostructure assemblies is important in using them as structural and functional materials. Carbon nanotubes (CNTs) lack the ability to reconstruct their entangled network. In this work, we report a strategy with which to realize efficient manipulation of CNT networks by forming double networks with branched polyethylenimine (PEI). The double network was highly viscoelastic and ductile and enabled efficient film stretching or creeping for CNT alignment, which dramatically improved the mechanical strength of the CNT films. Due to the viscous drag from the polymer network, the CNTs showed enhanced movability in reconstructing new networks, which made the film repairable. The repairability resulted from the branched polymeric structure. This double-networking strategy provides a new way to manipulate CNT assemblies for high-performance applications. In this work, we report a strategy with which to realize efficient manipulation of CNT networks by forming double networks with branched polyethylenimine (PEI). The double network was highly viscoelastic and ductile and enabled efficient film stretching or creeping for CNT alignment, which dramatically improved the mechanical strengths of the CNT films. Due to viscous drag from the polymer network, the CNTs showed enhanced movability in reconstructing new networks, which made the film repairable. The repairability resulted from the branched polymeric structure. This double-networking strategy provides a new way to manipulate CNT assemblies for high-performance applications.
{"title":"Viscoelastic, ductile and repairable carbon nanotube films formed with CNT/PEI double networks containing branched polyethylenimine","authors":"Xiaohua Zhang, Xin Wang, Xin Zhang, Jingyun Zou, Yongyi Zhang, Jingna Zhao, Qingwen Li","doi":"10.1038/s41427-023-00490-z","DOIUrl":"10.1038/s41427-023-00490-z","url":null,"abstract":"Manipulating nanostructure assemblies is important in using them as structural and functional materials. Carbon nanotubes (CNTs) lack the ability to reconstruct their entangled network. In this work, we report a strategy with which to realize efficient manipulation of CNT networks by forming double networks with branched polyethylenimine (PEI). The double network was highly viscoelastic and ductile and enabled efficient film stretching or creeping for CNT alignment, which dramatically improved the mechanical strength of the CNT films. Due to the viscous drag from the polymer network, the CNTs showed enhanced movability in reconstructing new networks, which made the film repairable. The repairability resulted from the branched polymeric structure. This double-networking strategy provides a new way to manipulate CNT assemblies for high-performance applications. In this work, we report a strategy with which to realize efficient manipulation of CNT networks by forming double networks with branched polyethylenimine (PEI). The double network was highly viscoelastic and ductile and enabled efficient film stretching or creeping for CNT alignment, which dramatically improved the mechanical strengths of the CNT films. Due to viscous drag from the polymer network, the CNTs showed enhanced movability in reconstructing new networks, which made the film repairable. The repairability resulted from the branched polymeric structure. This double-networking strategy provides a new way to manipulate CNT assemblies for high-performance applications.","PeriodicalId":19382,"journal":{"name":"Npg Asia Materials","volume":"15 1","pages":"1-12"},"PeriodicalIF":8.6,"publicationDate":"2023-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41427-023-00490-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48639755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-04DOI: 10.1038/s41427-023-00489-6
Zhen Song, You-Shan Zhang, Jing-Yi Shen, Bing Lin, Jie Wu, Ping-Hua Xiang, Chun-Gang Duan, Rui-Hua He
Perovskite iridates are a promising material platform for hosting unconventional superconductivity. Transport measurements of Sr2IrO4 thin-film field-effect transistors are expected to provide irrefutable evidence for the existence of superconductivity. However, these experiments have revealed a remarkably robust insulating state over wide electron and hole doping ranges; this finding is in contrast to the case of the bulk material, in which metallicity appears upon moderate electron doping by substituting cations in place of Sr. The nature of this robust insulating state and whether any metallic state can be realized in the Sr2IrO4 thin film are two remaining challenges that preclude further progress in the search for superconductivity in this system. Here, we show that this insulating state is enhanced in Sr2IrO4 thin films by thermal annealing under vacuum conditions, while it can be destroyed upon annealing in an oxygen atmosphere within restricted ranges of oxygen pressure, annealing temperature and ion substitution levels. The resulting films exhibit metallic transport behavior near room temperature and a metal–insulator crossover at ~200 K. Our results point to the potentially important roles of the oxygen vacancies at different atomic sites in the formation of the robust insulating state and the new metallic state and to their interplay in the Sr2IrO4 thin film. This finding opens new possibilities in the search for unconventional superconductivity by further tailoring the as-found metallic state in properly oxygen-annealed Sr2IrO4 thin films. Despite enormous efforts by many research groups, Sr2IrO4 was found to stay remarkably insulating in thin film form. Now, a high-pressure oxygen annealing treatment on the Sr2IrO4 thin film realized the long-sought metallicity for the first time. An emerging transport phase diagram was deduced from the experiment that features an interplay between two states: the robust insulating state, which is likely dominated by the defect scattering effect of planar oxygen vacancies O(2), and the new metallic state, which likely reflects an intrinsic bulk-like property of the IrO2 planes with effective electron doping due to apical oxygen vacancies O(1).
{"title":"Realizing metallicity in Sr2IrO4 thin films by high-pressure oxygen annealing","authors":"Zhen Song, You-Shan Zhang, Jing-Yi Shen, Bing Lin, Jie Wu, Ping-Hua Xiang, Chun-Gang Duan, Rui-Hua He","doi":"10.1038/s41427-023-00489-6","DOIUrl":"10.1038/s41427-023-00489-6","url":null,"abstract":"Perovskite iridates are a promising material platform for hosting unconventional superconductivity. Transport measurements of Sr2IrO4 thin-film field-effect transistors are expected to provide irrefutable evidence for the existence of superconductivity. However, these experiments have revealed a remarkably robust insulating state over wide electron and hole doping ranges; this finding is in contrast to the case of the bulk material, in which metallicity appears upon moderate electron doping by substituting cations in place of Sr. The nature of this robust insulating state and whether any metallic state can be realized in the Sr2IrO4 thin film are two remaining challenges that preclude further progress in the search for superconductivity in this system. Here, we show that this insulating state is enhanced in Sr2IrO4 thin films by thermal annealing under vacuum conditions, while it can be destroyed upon annealing in an oxygen atmosphere within restricted ranges of oxygen pressure, annealing temperature and ion substitution levels. The resulting films exhibit metallic transport behavior near room temperature and a metal–insulator crossover at ~200 K. Our results point to the potentially important roles of the oxygen vacancies at different atomic sites in the formation of the robust insulating state and the new metallic state and to their interplay in the Sr2IrO4 thin film. This finding opens new possibilities in the search for unconventional superconductivity by further tailoring the as-found metallic state in properly oxygen-annealed Sr2IrO4 thin films. Despite enormous efforts by many research groups, Sr2IrO4 was found to stay remarkably insulating in thin film form. Now, a high-pressure oxygen annealing treatment on the Sr2IrO4 thin film realized the long-sought metallicity for the first time. An emerging transport phase diagram was deduced from the experiment that features an interplay between two states: the robust insulating state, which is likely dominated by the defect scattering effect of planar oxygen vacancies O(2), and the new metallic state, which likely reflects an intrinsic bulk-like property of the IrO2 planes with effective electron doping due to apical oxygen vacancies O(1).","PeriodicalId":19382,"journal":{"name":"Npg Asia Materials","volume":"15 1","pages":"1-7"},"PeriodicalIF":8.6,"publicationDate":"2023-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41427-023-00489-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41569274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-21DOI: 10.1038/s41427-023-00488-7
Peng Liu, Dongsheng Yuan, Chao Dong, Gaoting Lin, Encarnación G. Víllora, Ji Qi, Xinguo Zhao, Kiyoshi Shimamura, Jie Ma, Junfeng Wang, Zhidong Zhang, Bing Li
Magnetic refrigeration around the liquid-helium temperature plays a critical role in many technological sectors. Even if gallium gadolinium garnet (GGG) has been regarded as the benchmark, its application is highly limited by the small magnetic entropy changes, the requirement of superconducting magnets, and the large device sizes. Here, we report that LiREF4 (RE = rare earth) single crystals exhibit significantly superior magnetocaloric performance levels to commercial GGG. Under a small magnetic field of 5 kOe, which can be easily achieved by a permanent magnet, the magnetic entropy change reaches a record-high value of 16.7 J kg−1 K−1 in LiHoF4 in contrast to the value of 1.0 J kg−1 K−1 in GGG. The combination of small driving fields, large entropy changes, and excellent thermal and/or magnetic reversibility enables this series to be employed as the ideal working material for compact magnetic refrigeration around the liquid-helium temperature. Compact and sustainable magnetic refrigeration technology can achieve unprecedented performance using lithium rare earth fluorides. For over a century, researchers have realized that magnetic fields can heat up or cool down other magnets thanks to magnetic entropy, the thermodynamic energy released when spins align or de-align. Finding magnets with sufficient thermal response for refrigeration has been a long-standing challenge. Now, Peng Liu from the University of Science and Technology of China in Shenyang and colleagues report that lithium holmium fluorides (LiHoF4) show record-setting magnetic entropy changes around liquid-helium temperatures, about 16 times larger than those of commercial magnetic refrigeration crystals. The entire chemical family of lithium rare earth fluorides measured by the team showed remarkable magnetic entropy changes under very small driving magnetic fields. The single crystals of lithium rare earth fluorides exhibit remarkable magnetocaloric performance with a record-high entropy change of 16.73 J kg-1 K-1 achieved under a very small magnetic field of 5 kOe.
{"title":"Ultralow-field magnetocaloric materials for compact magnetic refrigeration","authors":"Peng Liu, Dongsheng Yuan, Chao Dong, Gaoting Lin, Encarnación G. Víllora, Ji Qi, Xinguo Zhao, Kiyoshi Shimamura, Jie Ma, Junfeng Wang, Zhidong Zhang, Bing Li","doi":"10.1038/s41427-023-00488-7","DOIUrl":"10.1038/s41427-023-00488-7","url":null,"abstract":"Magnetic refrigeration around the liquid-helium temperature plays a critical role in many technological sectors. Even if gallium gadolinium garnet (GGG) has been regarded as the benchmark, its application is highly limited by the small magnetic entropy changes, the requirement of superconducting magnets, and the large device sizes. Here, we report that LiREF4 (RE = rare earth) single crystals exhibit significantly superior magnetocaloric performance levels to commercial GGG. Under a small magnetic field of 5 kOe, which can be easily achieved by a permanent magnet, the magnetic entropy change reaches a record-high value of 16.7 J kg−1 K−1 in LiHoF4 in contrast to the value of 1.0 J kg−1 K−1 in GGG. The combination of small driving fields, large entropy changes, and excellent thermal and/or magnetic reversibility enables this series to be employed as the ideal working material for compact magnetic refrigeration around the liquid-helium temperature. Compact and sustainable magnetic refrigeration technology can achieve unprecedented performance using lithium rare earth fluorides. For over a century, researchers have realized that magnetic fields can heat up or cool down other magnets thanks to magnetic entropy, the thermodynamic energy released when spins align or de-align. Finding magnets with sufficient thermal response for refrigeration has been a long-standing challenge. Now, Peng Liu from the University of Science and Technology of China in Shenyang and colleagues report that lithium holmium fluorides (LiHoF4) show record-setting magnetic entropy changes around liquid-helium temperatures, about 16 times larger than those of commercial magnetic refrigeration crystals. The entire chemical family of lithium rare earth fluorides measured by the team showed remarkable magnetic entropy changes under very small driving magnetic fields. The single crystals of lithium rare earth fluorides exhibit remarkable magnetocaloric performance with a record-high entropy change of 16.73 J kg-1 K-1 achieved under a very small magnetic field of 5 kOe.","PeriodicalId":19382,"journal":{"name":"Npg Asia Materials","volume":"15 1","pages":"1-9"},"PeriodicalIF":8.6,"publicationDate":"2023-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41427-023-00488-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48270383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-14DOI: 10.1038/s41427-023-00487-8
Lintian Yuan, Xuancheng Fu, Wen Yu, Huagen Wei, Fan dong, Ludan Zhang, Guiyan Wang, Huihua Dong, Fengting Lv, Yuguang Wang
Bacterial infections pose a severe threat to human health due to the exacerbation of antibiotic resistance and intracellular bacterial infections. Research suggests that oligo(p-phenylene vinylene) (OPV), commonly employed in the manufacture of organic solar batteries, can help address this issue. This study demonstrates the ability of OPV to target and sterilize intracellular Porphyromonas gingivalis and methicillin-resistant Staphylococcus aureus (MRSA) photodynamically. Most notably, OPV specifically targets bacteria without affecting healthy cells under dark conditions. Its chemical composition includes a conjugated backbone and ionic imidazole side chains, which allow OPV to bind to cell membranes. Furthermore, dental blue light curing lamps may excite OPV. Compared with antibiotics and traditional photosensitizers, OPV proves to be a potentially superior solution to eradicate intracellular microbial infections, both in fundamental research and clinical applications. This paper introduces OPV, an organic semiconductor material, as a novel photosensitizer to kill intracellular bacteria that are infectious and antibiotic-resistant. It explains how OPV binds to bacterial membranes and produces reactive oxygen species by blue light, guiding photodynamic therapy design. It proves the excellent antibacterial effect of OPV against Porphyromonas gingivalis and MRSA in vitro and in vivo, without damaging normal cells or tissues, indicating good biocompatibility and safety. It also shows that OPV can be excited by dental blue light curing lamps, facilitating clinical applications.
{"title":"Nowhere to run: oligo (p-phenylene vinylene) kills oral intracellular bacteria photodynamically","authors":"Lintian Yuan, Xuancheng Fu, Wen Yu, Huagen Wei, Fan dong, Ludan Zhang, Guiyan Wang, Huihua Dong, Fengting Lv, Yuguang Wang","doi":"10.1038/s41427-023-00487-8","DOIUrl":"10.1038/s41427-023-00487-8","url":null,"abstract":"Bacterial infections pose a severe threat to human health due to the exacerbation of antibiotic resistance and intracellular bacterial infections. Research suggests that oligo(p-phenylene vinylene) (OPV), commonly employed in the manufacture of organic solar batteries, can help address this issue. This study demonstrates the ability of OPV to target and sterilize intracellular Porphyromonas gingivalis and methicillin-resistant Staphylococcus aureus (MRSA) photodynamically. Most notably, OPV specifically targets bacteria without affecting healthy cells under dark conditions. Its chemical composition includes a conjugated backbone and ionic imidazole side chains, which allow OPV to bind to cell membranes. Furthermore, dental blue light curing lamps may excite OPV. Compared with antibiotics and traditional photosensitizers, OPV proves to be a potentially superior solution to eradicate intracellular microbial infections, both in fundamental research and clinical applications. This paper introduces OPV, an organic semiconductor material, as a novel photosensitizer to kill intracellular bacteria that are infectious and antibiotic-resistant. It explains how OPV binds to bacterial membranes and produces reactive oxygen species by blue light, guiding photodynamic therapy design. It proves the excellent antibacterial effect of OPV against Porphyromonas gingivalis and MRSA in vitro and in vivo, without damaging normal cells or tissues, indicating good biocompatibility and safety. It also shows that OPV can be excited by dental blue light curing lamps, facilitating clinical applications.","PeriodicalId":19382,"journal":{"name":"Npg Asia Materials","volume":"15 1","pages":"1-16"},"PeriodicalIF":8.6,"publicationDate":"2023-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41427-023-00487-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41821629","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The design of perovskite structures with multiferroic magnetoelectric coupling effects opens up new opportunities in fields such as the creation of next-generation spin-dependent multistate information storage technologies. In this work, we prepared a transition metal-implanted perovskite with multiferroic magnetoelectric coupling, in which both magnetoelectric coupling and a blueshift of photoluminescence were observed. The introduction of transition metal-generated polarized spin interacts with the electronic orbit through spin–orbital coupling to lead to a pronounced octahedron distortion, where the temperature dependence of the dielectric constant undergoes a ferroelectric polarization transition. An external magnetic field could enhance the strength of spin polarization to further affect the magnitude of electric polarization. Moreover, applying an electric field tunes the distortion of the octahedron dependence of electric polarization to feed back to the change in spin polarization. Overall, the spin polarization-induced electric polarization in perovskites provides a unique approach to realizing the room-temperature magnetoelectric coupling of multiferroic materials. The coexistence of ferroelectricity and ferromagnetism has been a traditional challenge for a long time. In this work, we propose a method of transition metal implantation into hybrid perovskites, which realizes the mutual regulation of magnetism and electricity, and obtains an obvious multiferroic magnetic-electric coupling effect. This study provides a new idea for realizing room-temperature magnetoelectric coupling of multiferroic materials employing ion implantation and paves the way for the realization of a new generation of spin-dependent electronic devices.
{"title":"Octahedron distortion-triggered dipole–spin interaction in multiferroic magnetoelectric perovskites","authors":"Xiangqian Lu, Renjie Hu, Yabin Zhu, Kepeng Song, Wei Qin","doi":"10.1038/s41427-023-00485-w","DOIUrl":"10.1038/s41427-023-00485-w","url":null,"abstract":"The design of perovskite structures with multiferroic magnetoelectric coupling effects opens up new opportunities in fields such as the creation of next-generation spin-dependent multistate information storage technologies. In this work, we prepared a transition metal-implanted perovskite with multiferroic magnetoelectric coupling, in which both magnetoelectric coupling and a blueshift of photoluminescence were observed. The introduction of transition metal-generated polarized spin interacts with the electronic orbit through spin–orbital coupling to lead to a pronounced octahedron distortion, where the temperature dependence of the dielectric constant undergoes a ferroelectric polarization transition. An external magnetic field could enhance the strength of spin polarization to further affect the magnitude of electric polarization. Moreover, applying an electric field tunes the distortion of the octahedron dependence of electric polarization to feed back to the change in spin polarization. Overall, the spin polarization-induced electric polarization in perovskites provides a unique approach to realizing the room-temperature magnetoelectric coupling of multiferroic materials. The coexistence of ferroelectricity and ferromagnetism has been a traditional challenge for a long time. In this work, we propose a method of transition metal implantation into hybrid perovskites, which realizes the mutual regulation of magnetism and electricity, and obtains an obvious multiferroic magnetic-electric coupling effect. This study provides a new idea for realizing room-temperature magnetoelectric coupling of multiferroic materials employing ion implantation and paves the way for the realization of a new generation of spin-dependent electronic devices.","PeriodicalId":19382,"journal":{"name":"Npg Asia Materials","volume":"15 1","pages":"1-8"},"PeriodicalIF":8.6,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41427-023-00485-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43029434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An understanding of the phase transitions at the nanoscale is essential in state-of-the-art engineering1–5, instead of simply averaging the heterogeneous domains formed during phase transitions6,7. However, as materials are scaled down, the steepness of the phase transition rapidly increases8–13 and requires extremely high precision in the control method. Here, a three-terminal device, which could precisely control the phase transition electrically14–19, was applied for the first time to a scaled-down metal-insulator transition material VO2. The crossover from continuous to binary transitions with the scaled-down material was clarified, and the critical channel length was successfully elucidated via phase boundary energy. Notably, below the critical channel length, the spatial degrees of freedom degenerated, and the impact of drain voltage application disappeared in the phase transition, indicating zero-dimensionality of the VO2 channel. This zero-dimensionality could be the fundamental property in the scaled-down phase transition and have a significant impact on various fields that need nanoscale engineering. Controlling the atomic configuration of nanoscale devices to alter their electrical properties has been demonstrated by scientists in Japan. The crystalline structure of a solid can switch between atomic arrangements, or phases, with a change in temperature or electric field. Devices that control these phase transitions have potential applications as computer memories or sensors but such control becomes more difficult as the device gets smaller. Takeaki Yajima from Kyusyu University, Fukuoka, and colleagues have demonstrated the electrically induced change from a metallic to an insulating phase in long, thin, submicrometer vanadium dioxide devices. The team showed that while longer devices exhibited a continuous transition between the two phases as a voltage was applied, the submicrometer devices unexpectedly showed a completely binary switching behavior. Knowing about this different behavior will aid the engineering of nanoscale electronic devices. Although the electrostatic tuning by three-terminal devices is generally weak for phase transition materials, it can control phases with much hither precision than temperature or pressure. This technique was applied to the scaled-down VO2 metal-insulator transitions, where the material phase is controlled by the gate voltage. The crossover from continuous to binary transition with scaling down was demonstrated, and the critical channel length was given by domain boundary instability. Interestingly, below the critical channel length, the influence of the noncritical stimulus (drain voltage in this case) disappeared because the spatial degree of freedom is lost in the single-domain VO2 channel.
{"title":"Zero-dimensionality of a scaled-down VO2 metal-insulator transition via high-resolution electrostatic gating","authors":"Takeaki Yajima, Yusuke Samata, Satoshi Hamasuna, Satya Prakash Pati, Akira Toriumi","doi":"10.1038/s41427-023-00486-9","DOIUrl":"10.1038/s41427-023-00486-9","url":null,"abstract":"An understanding of the phase transitions at the nanoscale is essential in state-of-the-art engineering1–5, instead of simply averaging the heterogeneous domains formed during phase transitions6,7. However, as materials are scaled down, the steepness of the phase transition rapidly increases8–13 and requires extremely high precision in the control method. Here, a three-terminal device, which could precisely control the phase transition electrically14–19, was applied for the first time to a scaled-down metal-insulator transition material VO2. The crossover from continuous to binary transitions with the scaled-down material was clarified, and the critical channel length was successfully elucidated via phase boundary energy. Notably, below the critical channel length, the spatial degrees of freedom degenerated, and the impact of drain voltage application disappeared in the phase transition, indicating zero-dimensionality of the VO2 channel. This zero-dimensionality could be the fundamental property in the scaled-down phase transition and have a significant impact on various fields that need nanoscale engineering. Controlling the atomic configuration of nanoscale devices to alter their electrical properties has been demonstrated by scientists in Japan. The crystalline structure of a solid can switch between atomic arrangements, or phases, with a change in temperature or electric field. Devices that control these phase transitions have potential applications as computer memories or sensors but such control becomes more difficult as the device gets smaller. Takeaki Yajima from Kyusyu University, Fukuoka, and colleagues have demonstrated the electrically induced change from a metallic to an insulating phase in long, thin, submicrometer vanadium dioxide devices. The team showed that while longer devices exhibited a continuous transition between the two phases as a voltage was applied, the submicrometer devices unexpectedly showed a completely binary switching behavior. Knowing about this different behavior will aid the engineering of nanoscale electronic devices. Although the electrostatic tuning by three-terminal devices is generally weak for phase transition materials, it can control phases with much hither precision than temperature or pressure. This technique was applied to the scaled-down VO2 metal-insulator transitions, where the material phase is controlled by the gate voltage. The crossover from continuous to binary transition with scaling down was demonstrated, and the critical channel length was given by domain boundary instability. Interestingly, below the critical channel length, the influence of the noncritical stimulus (drain voltage in this case) disappeared because the spatial degree of freedom is lost in the single-domain VO2 channel.","PeriodicalId":19382,"journal":{"name":"Npg Asia Materials","volume":"15 1","pages":"1-6"},"PeriodicalIF":8.6,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41427-023-00486-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49161395","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-23DOI: 10.1038/s41427-023-00483-y
Suhail K. Siddique, Hassan Sadek, Chi-Wei Wang, Chang-Chun Lee, Cheng-Yuan Tsai, Shou-Yi Chang, Chia-Lin Li, Chun-Hway Hsueh, Rong-Ming Ho
Herein, this work aims to develop a facile method for the fabrication of metallic mechanical metamaterial with a well-ordered diamond structure from a bottom-up approach using a self-assembled block copolymer for templated electrochemical deposition. By controlling the effective volume fraction of PDMS in PS-b-PDMS via solvent annealing followed by HF etching of PDMS, it is feasible to obtain nanoporous PS with diamond-structured nanochannels and used it as a template for templated electrochemical deposition. Subsequently, well-ordered nanonetwork gold (Au) can be fabricated. As evidenced by nanoindentation and micro-compression tests, the mechanical properties of the diamond-structured Au after removal of PS give the combination of lightweight and mechanically robust characteristics with an exceptionally high reduced elastic modulus of 11.9 ± 0.6 GPa and yield strength of 193 ± 11 MPa above the Hashin-Shtrikman upper bound of 72 MPa with a bending-dominated structure at equivalent density. The corresponding deformation mechanism can be elucidated by morphological observations experimentally and finite element analysis (FEA) numerically. This work demonstrates the bottom-up approach to fabricating metallic monolith with diamond structure in the nanoscale, giving a superior performance as mechanical metamaterials. This work aims to fabricate well-ordered nanonetwork Au through a bottom-up approach using templated electrochemical deposition for enhanced mechanical properties. As evidenced by nanoindentation and micro-compression tests, diamond-structured Au fabricated exhibits high reduced modulus and yield strength above the Hashin-Shtrikman upper bound due to the deliberate structuring and nanosized effects.
{"title":"Diamond-structured nanonetwork gold as mechanical metamaterials from bottom-up approach","authors":"Suhail K. Siddique, Hassan Sadek, Chi-Wei Wang, Chang-Chun Lee, Cheng-Yuan Tsai, Shou-Yi Chang, Chia-Lin Li, Chun-Hway Hsueh, Rong-Ming Ho","doi":"10.1038/s41427-023-00483-y","DOIUrl":"10.1038/s41427-023-00483-y","url":null,"abstract":"Herein, this work aims to develop a facile method for the fabrication of metallic mechanical metamaterial with a well-ordered diamond structure from a bottom-up approach using a self-assembled block copolymer for templated electrochemical deposition. By controlling the effective volume fraction of PDMS in PS-b-PDMS via solvent annealing followed by HF etching of PDMS, it is feasible to obtain nanoporous PS with diamond-structured nanochannels and used it as a template for templated electrochemical deposition. Subsequently, well-ordered nanonetwork gold (Au) can be fabricated. As evidenced by nanoindentation and micro-compression tests, the mechanical properties of the diamond-structured Au after removal of PS give the combination of lightweight and mechanically robust characteristics with an exceptionally high reduced elastic modulus of 11.9 ± 0.6 GPa and yield strength of 193 ± 11 MPa above the Hashin-Shtrikman upper bound of 72 MPa with a bending-dominated structure at equivalent density. The corresponding deformation mechanism can be elucidated by morphological observations experimentally and finite element analysis (FEA) numerically. This work demonstrates the bottom-up approach to fabricating metallic monolith with diamond structure in the nanoscale, giving a superior performance as mechanical metamaterials. This work aims to fabricate well-ordered nanonetwork Au through a bottom-up approach using templated electrochemical deposition for enhanced mechanical properties. As evidenced by nanoindentation and micro-compression tests, diamond-structured Au fabricated exhibits high reduced modulus and yield strength above the Hashin-Shtrikman upper bound due to the deliberate structuring and nanosized effects.","PeriodicalId":19382,"journal":{"name":"Npg Asia Materials","volume":"15 1","pages":"1-12"},"PeriodicalIF":8.6,"publicationDate":"2023-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41427-023-00483-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43020981","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：