Gabriel E. Marcus, Timothy W. Carlson, Kadaba Swathi, David Carroll
In this work, we examine the formation of iron-based magnetic domains on two-dimensional (2D) single-crystal bismuth telluride plates. Using solvothermal chemical methods, 2D bismuth telluride (Bi2Te3) single crystalline nanoplates were reacted with iron salts (FeCl2) to achieve electrical doping. The use of a reducing agent [L(+)-ascorbic acid] along with FeCl2 resulted in homogeneous dispersion of iron across the crystal, whereas non-reduced iron doping achieved edge growth of iron/iron oxide nanoparticles. High-resolution analytical electron microscopy was used to examine the iron nanoparticle accumulation and morphology at nanoplate edges for non-reduced materials and iron dispersions within the crystals in the case of reduction. Our analysis revealed little variation in the atomic uptake of iron in any form over a range of solution-dopant concentrations. However, structural analysis and transport measurements clearly indicate the tendency of the dopant nanoparticles to oxidize quickly. The Seebeck coefficient and power factor also express modifications with exposure to oxidation, providing an indirect probe of the dopant modification to the host Bi2Te3’s electronic properties. Importantly, however, magnetic force microscopy images show a distinct difference in the formation of magnetic phases with and without the use of reducing agents during iron doping. This suggests that oxidation post-doping does not form magnetic phases, whereas oxidation during the doping process is suitable for obtaining magnetically doped Bi2Te3 nanocrystals.
{"title":"Solution-based iron doping of solvothermally grown 2D hexagonal bismuth telluride","authors":"Gabriel E. Marcus, Timothy W. Carlson, Kadaba Swathi, David Carroll","doi":"10.1063/5.0220681","DOIUrl":"https://doi.org/10.1063/5.0220681","url":null,"abstract":"In this work, we examine the formation of iron-based magnetic domains on two-dimensional (2D) single-crystal bismuth telluride plates. Using solvothermal chemical methods, 2D bismuth telluride (Bi2Te3) single crystalline nanoplates were reacted with iron salts (FeCl2) to achieve electrical doping. The use of a reducing agent [L(+)-ascorbic acid] along with FeCl2 resulted in homogeneous dispersion of iron across the crystal, whereas non-reduced iron doping achieved edge growth of iron/iron oxide nanoparticles. High-resolution analytical electron microscopy was used to examine the iron nanoparticle accumulation and morphology at nanoplate edges for non-reduced materials and iron dispersions within the crystals in the case of reduction. Our analysis revealed little variation in the atomic uptake of iron in any form over a range of solution-dopant concentrations. However, structural analysis and transport measurements clearly indicate the tendency of the dopant nanoparticles to oxidize quickly. The Seebeck coefficient and power factor also express modifications with exposure to oxidation, providing an indirect probe of the dopant modification to the host Bi2Te3’s electronic properties. Importantly, however, magnetic force microscopy images show a distinct difference in the formation of magnetic phases with and without the use of reducing agents during iron doping. This suggests that oxidation post-doping does not form magnetic phases, whereas oxidation during the doping process is suitable for obtaining magnetically doped Bi2Te3 nanocrystals.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"298 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141884536","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}
Tissue repair and regeneration are critical processes for maintaining the integrity and function of various organs and tissues. Recently, polysaccharide materials and protein materials have garnered interest for use in tissue repair strategies. However, polysaccharides are more stable and unaffected by temperature and pH changes compared to proteins, and some polysaccharides can provide stronger mechanical support, which is particularly important for constructing tissue-engineered scaffolds and wound dressings. This Review provides an in-depth overview of the origins of polysaccharides, the advantages of polysaccharide materials, and processing and design strategies. In addition, the potential of polysaccharide materials for the restoration of tissues such as skin, heart, and nerves is highlighted. Finally, we discuss in depth the challenges that polysaccharide materials still face in tissue repair, such as the stability of the material, regulating mechanical characteristics and deterioration rates under different conditions. To achieve more effective tissue repair and regeneration, future research must focus on further improving the characteristics and functionalities of polysaccharide materials.
{"title":"Designing polysaccharide materials for tissue repair and regeneration","authors":"Anqi Jin, Yunyuan Shao, Fangyan Wang, Jiayin Feng, Lanjie Lei, Minghai Dai","doi":"10.1063/5.0223937","DOIUrl":"https://doi.org/10.1063/5.0223937","url":null,"abstract":"Tissue repair and regeneration are critical processes for maintaining the integrity and function of various organs and tissues. Recently, polysaccharide materials and protein materials have garnered interest for use in tissue repair strategies. However, polysaccharides are more stable and unaffected by temperature and pH changes compared to proteins, and some polysaccharides can provide stronger mechanical support, which is particularly important for constructing tissue-engineered scaffolds and wound dressings. This Review provides an in-depth overview of the origins of polysaccharides, the advantages of polysaccharide materials, and processing and design strategies. In addition, the potential of polysaccharide materials for the restoration of tissues such as skin, heart, and nerves is highlighted. Finally, we discuss in depth the challenges that polysaccharide materials still face in tissue repair, such as the stability of the material, regulating mechanical characteristics and deterioration rates under different conditions. To achieve more effective tissue repair and regeneration, future research must focus on further improving the characteristics and functionalities of polysaccharide materials.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"75 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141884955","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}
We investigated the thermal-history dependence of physical properties in a quenched Fe5−xGeTe2 (x ∼ 0.16) single crystal by measuring magnetization (M), electrical resistivity (ρ), Seebeck coefficient (S), and thermal conductivity (κ) as a function of temperature (T). The results reveal anomalies in these physical quantities around various transition points: ferromagnetic (TC ∼ 310–300 K), helimagnetic (TH ∼ 275 K), charge ordering (TCO ∼ 165 K), spin-reorientation (T* ∼ 100–120 K), and a Fermi-liquid (FL) phase below TL ∼ 35 K. Using power-law fitting, the M(T) analysis near TC shows that Fe moments become primarily itinerant after thermal cycling. The ρ(T) results indicate inherent residual stresses in the crystal that alter with thermal cycling, influencing ferromagnetic domain formations within grain boundaries. The system exhibits a strongly correlated FL behavior at low temperatures, which ceases above TL due to spin fluctuations. In the T-range of T* ≤ T ≤ TCO, ρ(T) and S(T) analyses suggest significant electronic band structure modifications with multiband effects. The κ(T) data indicate phonon-dominated heat transport in the crystal, with a phonon behavior influenced by inherent lattice strains following initial thermal cycles, as evidenced by the decreased phonon peak height at low temperatures. In addition, there is evidence of phonon localization and electron–phonon coupling at higher temperatures.
{"title":"Thermal history-dependent characteristics in van der Waals ferromagnet Fe5−xGeTe2 (x ∼ 0.16)","authors":"Ramesh Lalmani Yadav, Pallab Bag, Chien-Chih Lai, Yung-Kang Kuo, Chia-Nung Kuo, Chin-Shan Lue","doi":"10.1063/5.0215121","DOIUrl":"https://doi.org/10.1063/5.0215121","url":null,"abstract":"We investigated the thermal-history dependence of physical properties in a quenched Fe5−xGeTe2 (x ∼ 0.16) single crystal by measuring magnetization (M), electrical resistivity (ρ), Seebeck coefficient (S), and thermal conductivity (κ) as a function of temperature (T). The results reveal anomalies in these physical quantities around various transition points: ferromagnetic (TC ∼ 310–300 K), helimagnetic (TH ∼ 275 K), charge ordering (TCO ∼ 165 K), spin-reorientation (T* ∼ 100–120 K), and a Fermi-liquid (FL) phase below TL ∼ 35 K. Using power-law fitting, the M(T) analysis near TC shows that Fe moments become primarily itinerant after thermal cycling. The ρ(T) results indicate inherent residual stresses in the crystal that alter with thermal cycling, influencing ferromagnetic domain formations within grain boundaries. The system exhibits a strongly correlated FL behavior at low temperatures, which ceases above TL due to spin fluctuations. In the T-range of T* ≤ T ≤ TCO, ρ(T) and S(T) analyses suggest significant electronic band structure modifications with multiband effects. The κ(T) data indicate phonon-dominated heat transport in the crystal, with a phonon behavior influenced by inherent lattice strains following initial thermal cycles, as evidenced by the decreased phonon peak height at low temperatures. In addition, there is evidence of phonon localization and electron–phonon coupling at higher temperatures.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"81 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141884807","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}
Yunfei Xie, Shuyao Chen, Yucong Yang, Dong Gao, Qiuli Chen, Ziyue Bi, Yuhang Liu, Lei Bi, Haiyuan Chen, Donghua Liu, Tao Liu
This paper reports a strategy for more reliably obtaining sputtered thin yttrium–iron–garnet (YIG) films possessing both low magnetic damping (α) and a highly spin transparent surface, which represent two of the most important properties for YIG films applied in spintronic devices. The two key points of this strategy, concluded from our systematical studies, are as follows: oxygen reactive sputtering of a slight Y-rich YIG target to avoid the over-stoichiometry of the Fe component and at the same time minimize oxygen vacancy density; and employing phosphoric acid wet etching to remove the inevitable thin magnetic dead layer formed on the surface. The feasibility of this strategy was proved by the achievement of a high quality 30 nm-thick YIG film. It possesses a ferromagnetic resonance linewidth of only 3.4 Oe at 8 GHz, α of only 4.6 × 10−4, and a very spin-transparent surface, as proved by the measured extremely large spin pumping voltage of 650.1 µV after depositing a 3 nm Pt layer.
{"title":"A strategy for more reliably obtaining Y3Fe5O12 thin films with both low damping and highly spin transparent surface","authors":"Yunfei Xie, Shuyao Chen, Yucong Yang, Dong Gao, Qiuli Chen, Ziyue Bi, Yuhang Liu, Lei Bi, Haiyuan Chen, Donghua Liu, Tao Liu","doi":"10.1063/5.0202639","DOIUrl":"https://doi.org/10.1063/5.0202639","url":null,"abstract":"This paper reports a strategy for more reliably obtaining sputtered thin yttrium–iron–garnet (YIG) films possessing both low magnetic damping (α) and a highly spin transparent surface, which represent two of the most important properties for YIG films applied in spintronic devices. The two key points of this strategy, concluded from our systematical studies, are as follows: oxygen reactive sputtering of a slight Y-rich YIG target to avoid the over-stoichiometry of the Fe component and at the same time minimize oxygen vacancy density; and employing phosphoric acid wet etching to remove the inevitable thin magnetic dead layer formed on the surface. The feasibility of this strategy was proved by the achievement of a high quality 30 nm-thick YIG film. It possesses a ferromagnetic resonance linewidth of only 3.4 Oe at 8 GHz, α of only 4.6 × 10−4, and a very spin-transparent surface, as proved by the measured extremely large spin pumping voltage of 650.1 µV after depositing a 3 nm Pt layer.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"30 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141887087","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}
N. Lejeune, E. Fourneau, A. Barrera, O. Morris, O. Leonard, J. A. Arregi, C. Navau, V. Uhlíř, S. Bending, A. Palau, A. V. Silhanek
Transformation optics applied to low frequency magnetic systems have been recently implemented to design magnetic field concentrators and cloaks with superior performance. Although this achievement has been amply demonstrated theoretically and experimentally in bulk 3D macrostructures, the performance of these devices at low dimensions remains an open question. In this work, we numerically investigate the non-monotonic evolution of the gain of a magnetic metamaterial field concentrator as the axial dimension is progressively shrunk. In particular, we show that in planar structures, the role played by the diamagnetic components becomes negligible, whereas the paramagnetic elements increase their magnetic field channeling efficiency. This is further demonstrated experimentally by tracking the gain of superconductor-ferromagnet concentrators through the superconducting transition. Interestingly, for thicknesses where the diamagnetic petals play an important role in the concentration gain, they also help to reduce the stray field of the concentrator, thus limiting the perturbation of the external field (invisibility). Our findings establish a roadmap and set clear geometrical limits for designing low dimensional magnetic field concentrators.
{"title":"Dimensional crossover of microscopic magnetic metasurfaces for magnetic field amplification","authors":"N. Lejeune, E. Fourneau, A. Barrera, O. Morris, O. Leonard, J. A. Arregi, C. Navau, V. Uhlíř, S. Bending, A. Palau, A. V. Silhanek","doi":"10.1063/5.0217500","DOIUrl":"https://doi.org/10.1063/5.0217500","url":null,"abstract":"Transformation optics applied to low frequency magnetic systems have been recently implemented to design magnetic field concentrators and cloaks with superior performance. Although this achievement has been amply demonstrated theoretically and experimentally in bulk 3D macrostructures, the performance of these devices at low dimensions remains an open question. In this work, we numerically investigate the non-monotonic evolution of the gain of a magnetic metamaterial field concentrator as the axial dimension is progressively shrunk. In particular, we show that in planar structures, the role played by the diamagnetic components becomes negligible, whereas the paramagnetic elements increase their magnetic field channeling efficiency. This is further demonstrated experimentally by tracking the gain of superconductor-ferromagnet concentrators through the superconducting transition. Interestingly, for thicknesses where the diamagnetic petals play an important role in the concentration gain, they also help to reduce the stray field of the concentrator, thus limiting the perturbation of the external field (invisibility). Our findings establish a roadmap and set clear geometrical limits for designing low dimensional magnetic field concentrators.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"96 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141871637","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}
Modulating extracellular matrix (ECM) elasticity with fibrillar collagen offers great potential for regenerative medicine, drug discovery, and disease modeling by replicating in vivo mechanical signals. This enhances the understanding of cellular responses and fosters therapeutic innovation. However, precise ECM elasticity measurements are still lacking. This study couples time-resolved Brillouin spectroscopy and pulsed laser-induced Scholte wave generation. We measure how collagen fibrillation affects sound velocity and refractive index. These insights are advancing tissue engineering and cellular biomechanics.
{"title":"Complementarity between Brillouin signature and Scholte wave for controlled elasticity in fibrillated collagen medium for culture cell","authors":"A. Hamraoui, O. Sénépart, L. Belliard","doi":"10.1063/5.0225336","DOIUrl":"https://doi.org/10.1063/5.0225336","url":null,"abstract":"Modulating extracellular matrix (ECM) elasticity with fibrillar collagen offers great potential for regenerative medicine, drug discovery, and disease modeling by replicating in vivo mechanical signals. This enhances the understanding of cellular responses and fosters therapeutic innovation. However, precise ECM elasticity measurements are still lacking. This study couples time-resolved Brillouin spectroscopy and pulsed laser-induced Scholte wave generation. We measure how collagen fibrillation affects sound velocity and refractive index. These insights are advancing tissue engineering and cellular biomechanics.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"1 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141770184","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}
Metal–organic cycles/cages (MOCs) are a class of nanoscale molecular entities that possess distinct shapes and sizes and are designed and synthesized through the predictable integration of organic and inorganic ligands. The diverse functionalities of MOCs render them valuable in the fields of biology, chemistry, and materials. First, the cavity renders them suitable for host–guest interactions, which are subsequently employed to induce conformational changes, and this approach is particularly advantageous for catalysis, sensing, and controlled loading and release. Furthermore, MOC- and polymer-based aggregates can be applied in biomedical research and cascaded light-harvesting systems. Benefiting from the high specific surface area, the initial exploration of MOC-based hierarchical assemblies indicates their potential applications in biomedicine and catalysis. MOC-based microsheets and centimeter films can be used for dual-mode catalysis and novel wound dressing for nonhealing wounds. In addition, the design and synthesis of novel MOCs with different shapes and sizes through various strategies are discussed. We summarized the latest progress in the past 5 years in this Review.
金属有机环/笼（MOCs）是一类具有独特形状和尺寸的纳米级分子实体，通过有机和无机配体的可预测整合而设计合成。MOCs 的多种功能使其在生物、化学和材料领域具有重要价值。首先，空腔使其适用于宿主与客体之间的相互作用，随后利用这种相互作用诱导构象变化，这种方法在催化、传感、控制装载和释放方面尤其具有优势。此外，基于 MOC 和聚合物的聚合体还可应用于生物医学研究和级联光收集系统。得益于高比表面积，对基于 MOC 的分层集合体的初步探索显示了它们在生物医学和催化领域的潜在应用。基于 MOC 的微片和厘米薄膜可用于双模催化和治疗不愈合伤口的新型伤口敷料。此外，我们还讨论了通过各种策略设计和合成不同形状和尺寸的新型 MOC。我们在这篇综述中总结了过去 5 年的最新进展。
{"title":"Design and synthesis of metal–organic cycles/cages (MOCs) and their applications","authors":"Yuanyuan Li, Fengmin Zhang, Yan Sun","doi":"10.1063/5.0225164","DOIUrl":"https://doi.org/10.1063/5.0225164","url":null,"abstract":"Metal–organic cycles/cages (MOCs) are a class of nanoscale molecular entities that possess distinct shapes and sizes and are designed and synthesized through the predictable integration of organic and inorganic ligands. The diverse functionalities of MOCs render them valuable in the fields of biology, chemistry, and materials. First, the cavity renders them suitable for host–guest interactions, which are subsequently employed to induce conformational changes, and this approach is particularly advantageous for catalysis, sensing, and controlled loading and release. Furthermore, MOC- and polymer-based aggregates can be applied in biomedical research and cascaded light-harvesting systems. Benefiting from the high specific surface area, the initial exploration of MOC-based hierarchical assemblies indicates their potential applications in biomedicine and catalysis. MOC-based microsheets and centimeter films can be used for dual-mode catalysis and novel wound dressing for nonhealing wounds. In addition, the design and synthesis of novel MOCs with different shapes and sizes through various strategies are discussed. We summarized the latest progress in the past 5 years in this Review.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"67 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141770257","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}
Grégoire Magagnin, Jordan Bouaziz, Martine Le Berre, Sara Gonzalez, Damien Deleruyelle, Bertrand Vilquin
Over the last fifteen years, ferroelectric (FE) and antiferroelectric (AFE) ultra-thin films based on fluorite-structured materials have drawn significant attention for a wide variety of applications requiring high integration density. AFE ZrO2, in particular, holds significant promise for nanosupercapacitors, owing to its potential for high energy storage density (ESD) and high efficiency (η). This work assesses the potential of high-performance Hf1−xZrxO2 thin films encapsulated by TiN electrodes that show linear dielectric (LD), FE, and AFE behavior. A wake-up effect is observed for AFE ZrO2, a phenomenon barely reported for pure zirconium oxide and AFE materials in general, correlated with the disappearance of the pinched hysteresis loop commonly observed for Zr-doped HfO2 thin films. ESD and η are compared for FE, AFE, and LD samples at the same electrical field (3.5 MV/cm). As expected, ESD is higher for the FE sample (95 J/cm3), but η is ridiculously small (≈55%) because of the opening of the FE hysteresis curve, inducing high loss. Conversely, LD samples exhibit the highest efficiency (nearly 100%), at the expense of a lower ESD. AFE ZrO2 thin film strikes a balance between FE and LD behavior, showing reduced losses compared to the FE sample but an ESD as high as 52 J/cm3 at 3.5 MV/cm. This value can be further increased up to 84 J/cm3 at a higher electrical field (4.0 MV/cm), with an η of 75%, among the highest values reported for fluorite-structured materials, offering promising perspectives for future optimization.
{"title":"Comparative performance of fluorite-structured materials for nanosupercapacitor applications","authors":"Grégoire Magagnin, Jordan Bouaziz, Martine Le Berre, Sara Gonzalez, Damien Deleruyelle, Bertrand Vilquin","doi":"10.1063/5.0220110","DOIUrl":"https://doi.org/10.1063/5.0220110","url":null,"abstract":"Over the last fifteen years, ferroelectric (FE) and antiferroelectric (AFE) ultra-thin films based on fluorite-structured materials have drawn significant attention for a wide variety of applications requiring high integration density. AFE ZrO2, in particular, holds significant promise for nanosupercapacitors, owing to its potential for high energy storage density (ESD) and high efficiency (η). This work assesses the potential of high-performance Hf1−xZrxO2 thin films encapsulated by TiN electrodes that show linear dielectric (LD), FE, and AFE behavior. A wake-up effect is observed for AFE ZrO2, a phenomenon barely reported for pure zirconium oxide and AFE materials in general, correlated with the disappearance of the pinched hysteresis loop commonly observed for Zr-doped HfO2 thin films. ESD and η are compared for FE, AFE, and LD samples at the same electrical field (3.5 MV/cm). As expected, ESD is higher for the FE sample (95 J/cm3), but η is ridiculously small (≈55%) because of the opening of the FE hysteresis curve, inducing high loss. Conversely, LD samples exhibit the highest efficiency (nearly 100%), at the expense of a lower ESD. AFE ZrO2 thin film strikes a balance between FE and LD behavior, showing reduced losses compared to the FE sample but an ESD as high as 52 J/cm3 at 3.5 MV/cm. This value can be further increased up to 84 J/cm3 at a higher electrical field (4.0 MV/cm), with an η of 75%, among the highest values reported for fluorite-structured materials, offering promising perspectives for future optimization.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"46 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141770259","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}
Beatriz Sisniega, Roberto Fernández de Luis, Jon Gutiérrez, Alfredo García-Arribas
Relative humidity is a crucial parameter in several fields, such as air quality monitoring, food storage, or control of industrial processes. In this study, we propose a wireless humidity sensor based on magnetoelastic resonance sensors functionalized with Metal–Organic Frameworks (MOFs). Different MOF water harvesters were tested as sensor active coatings: MOF-801, MOF-808, UiO-66-NH2, Al-Fumarate, and CAU-23. Their water absorption capacity and overall performance, when integrated into the sensors, were evaluated. As expected, the selected MOFs showed promising water harvesting capacity, enabling a successful sensor response to humidity in a wide range of relative humidity: 3%–85%. These humidity sensors showed a great sensitivity, stability, and selectivity to water molecules. The response time of the devices was around 15 s, with stabilization and recovery times in adsorption and desorption processes of less than 1 min for certain ranges of operation. In addition to the satisfactory behavior as humidity sensors, magnetoelastic resonators have emerged as a promising tool for the characterization of the dynamic adsorption capacity of MOF materials, as they easily provide a quantitative measure of the water mass adsorbed by the material.
{"title":"Magnetoelastic resonators functionalized with metal–organic framework water harvesters as wireless humidity sensors","authors":"Beatriz Sisniega, Roberto Fernández de Luis, Jon Gutiérrez, Alfredo García-Arribas","doi":"10.1063/5.0206165","DOIUrl":"https://doi.org/10.1063/5.0206165","url":null,"abstract":"Relative humidity is a crucial parameter in several fields, such as air quality monitoring, food storage, or control of industrial processes. In this study, we propose a wireless humidity sensor based on magnetoelastic resonance sensors functionalized with Metal–Organic Frameworks (MOFs). Different MOF water harvesters were tested as sensor active coatings: MOF-801, MOF-808, UiO-66-NH2, Al-Fumarate, and CAU-23. Their water absorption capacity and overall performance, when integrated into the sensors, were evaluated. As expected, the selected MOFs showed promising water harvesting capacity, enabling a successful sensor response to humidity in a wide range of relative humidity: 3%–85%. These humidity sensors showed a great sensitivity, stability, and selectivity to water molecules. The response time of the devices was around 15 s, with stabilization and recovery times in adsorption and desorption processes of less than 1 min for certain ranges of operation. In addition to the satisfactory behavior as humidity sensors, magnetoelastic resonators have emerged as a promising tool for the characterization of the dynamic adsorption capacity of MOF materials, as they easily provide a quantitative measure of the water mass adsorbed by the material.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"54 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141770258","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}
Dongyeol Ju, Hyeonseung Ji, Jungwoo Lee, Sungjun Kim
The implementation of reservoir computing using resistive random-access memory as a physical reservoir has attracted attention due to its low training cost and high energy efficiency during parallel data processing. In this work, a NbOx/Al2O3-based memristor device was fabricated through a sputter and atomic layer deposition process to realize reservoir computing. The proposed device exhibits favorable resistive switching properties (>103 cycle endurance) and demonstrates short-term memory characteristics with current decay. Utilizing the controllability of the resistance state and its variability during cycle repetition, electrical pulses are applied to investigate the synapse-emulating properties of the device. The results showcase the functions of potentiation and depression, the coexistence of short-term and long-term plasticity, excitatory post-synaptic current, and spike-rate dependent plasticity. Building upon the functionalities of an artificial synapse, pulse spikes are categorized into three distinct neural firing patterns (normal, adapt, and boost) to implement 4-bit reservoir computing, enabling a significant distinction between “0” and “1.”
{"title":"Effect of neural firing pattern on NbOx/Al2O3 memristor-based reservoir computing system","authors":"Dongyeol Ju, Hyeonseung Ji, Jungwoo Lee, Sungjun Kim","doi":"10.1063/5.0211178","DOIUrl":"https://doi.org/10.1063/5.0211178","url":null,"abstract":"The implementation of reservoir computing using resistive random-access memory as a physical reservoir has attracted attention due to its low training cost and high energy efficiency during parallel data processing. In this work, a NbOx/Al2O3-based memristor device was fabricated through a sputter and atomic layer deposition process to realize reservoir computing. The proposed device exhibits favorable resistive switching properties (>103 cycle endurance) and demonstrates short-term memory characteristics with current decay. Utilizing the controllability of the resistance state and its variability during cycle repetition, electrical pulses are applied to investigate the synapse-emulating properties of the device. The results showcase the functions of potentiation and depression, the coexistence of short-term and long-term plasticity, excitatory post-synaptic current, and spike-rate dependent plasticity. Building upon the functionalities of an artificial synapse, pulse spikes are categorized into three distinct neural firing patterns (normal, adapt, and boost) to implement 4-bit reservoir computing, enabling a significant distinction between “0” and “1.”","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"61 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141770261","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}
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