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Thickness, Annealing, and Surface Roughness Effect on Magnetic and Significant Properties of Co40Fe40B10Dy10 Thin Films

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materials 2023年第17期16卷 5995页

作者： Liu, Wen-Jen Chang, Yung-Huang Chiang, Chia-Chin Chen, Yuan-Tsung Wang, Yu-Zhi Wu, Chueh-Lin Lin, Shih-Hung Ou, Sin-Liang Department of Materials Science and Engineering I-Shou University Kaohsiung84001 Taiwan Bachelor Program in Industrial Technology National Yunlin University of Science and Technology 123 University Road Section 3 Douliou64002 Taiwan Department of Mechanical Engineering National Kaohsiung University of Science and Technology Kaohsiung80778 Taiwan Graduate School of Materials Science National Yunlin University of Science and Technology 123 University Road Section 3 Douliou64002 Taiwan Department of Electronic Engineering National Yunlin University of Science and Technology 123 University Road Section 3 Douliou64002 Taiwan Bachelor Program for Design and Materials for Medical Equipment and Devices Da-Yeh University Changhua51591 Taiwan

In this study, Co40Fe40B10Dy10 thin films were deposited using a direct current (DC) magnetron sputtering technique. The films were deposited on glass substrates with thicknesses of 10, 20, 30, 40, and 50 nm, and heat-treated in a vacuum annealing furnace at 100, 200, and 300 °C. Various instruments were used to examine and analyze the effects of roughness on the magnetic, adhesive, and mechanical properties. From the low frequency alternating current magnetic susceptibility (χac) results, the optimum resonance frequency is 50 Hz, and the maximum χac value tends to increase with the increase in the thicknesses and annealing temperatures. The maximum χac value is 0.18 at a film thickness of 50 nm and an annealing temperature of 300 °C. From the four-point probe, it is found that the resistivity and sheet resistance values decrease with the increase in film deposition thicknesses and higher annealing temperatures. From the magnetic force microscopy (MFM), the stripe-like magnetic domain distribution is more obvious with the increase in annealing temperature. According to the contact angle data, at the same annealing temperature, the contact angle decreases as the thickness increases due to changes in surface morphology. The maximal surface energy value at 300 °C is 34.71 mJ/mm2. The transmittance decreases with increasing film thickness, while the absorption intensity is inversely proportional to the transmittance, implying that the thickness effect suppresses the photon signal. Smoother roughness has less domain pinning, more carrier conductivity, and less light scattering, resulting in superior magnetic, electrical, adhesive, and optical performance. © 2023 by the authors.

关键词： Thin films

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Thermal-Protective and Oxygen-Resistant Nanocoating Using Silica-Nanocomposites for Laser Thinning of Polymorphic Molybdenum Ditellurides

SSRN

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SSRN 2023年

作者： Heo, Soyoung Kim, Seulbi Lee, Seung Yeon Yang, Heejun Park, Ji Hun Cho, Suyeon Division of Chemical Engineering and Materials Science Graduate Program in System Health Science and Engineering Ewha Womans University Seoul03760 Korea Republic of Department of Science Education Ewha Womans University Seoul03760 Korea Republic of Daejeon34141 Korea Republic of

Laser irradiation has been investigated as a method of fabricating atomically-thin crystals from layered two-dimensional (2D) materials with precise thickness control. However, during laser irradiation, inevitable structural changes can occur in the 2D materials due to the high thermal energy, altering their physical and chemical properties and introducing disorder, which has hindered the study and use of the intrinsic properties of atomically-thin materials. In this study, we report a laser thinning method using a new coating material, a layered silica-based nanocomposite (SNC), that preserves the pristine crystal structure of a polymorphic 2D material, MoTe2, down to an atomically thin geometry. The nano-porous coating of layered silica-based nanocomposite (SNC) was robust against thermal heating and behaved as a good thermal-protective and oxygen-resistant material in the laser thinning process. Therefore, the SNC-coated MoTe2 flakes were successfully thinned down to atomically-thin geometry, while preserving their 2H structure. Accordingly, our SNC coating of 2D materials is a promising way to engineer the phase and geometry of polymorphic 2D materials, enabling versatile applications in various optoelectronic, spintronic, and electronic devices. © 2023, The Authors. All rights reserved.

关键词： Coatings

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High Cooling Rate Cells in Al-Ce Alloys: A Combined Experimental and Modelling Approach

SSRN

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SSRN 2023年

作者： Baraldi, Rafael Bispo da Silva, Douglas de Gouveia, Guilherme Lisboa Garcia, Amauri Spinelli, José Eduardo Department of Materials Engineering Federal University of São Carlos UFSCar SP São Carlos13565-905 Brazil Federal University of São Carlos Graduate Program in Materials Science and Engineering SP São Carlos13565-905 Brazil Department of Manufacturing and Materials Engineering University of Campinas SP Campinas13083-860 Brazil

Microstructures are the strategic link between cast alloys processing and their properties. The investigation of α-Al morphologies is regarded as critical for broadening the potential applications of cast Al-Ce alloys. These alloys are anticipated to offer high-temperature strength. Moreover, Ce is the most abundant rare-earth element in the Earth’s crust. A central task is changing the Ce content (4.0, 6.0 and 10.1 wt.% Ce) and observing the morphologies, particularly when extremely high cooling rates - 102 to 103 K/s - are attained during cast-centrifugal Cu-mold operations. In the present contribution, rapid solidification of the Al-4wt.% Ce alloy led to generation of high cooling rate cells. A eutectic mixture of Al11Ce3 fibers and lamellae filled the intercellular spacings. Using the Hunt-Lu model, an experimental cell spacing of roughly 6.3 μm was obtained with a suitable equivalence to the modeling outcomes, corresponding to a solidification velocity of 3.1 mm/s and a cooling rate of approximately 155 K/s. © 2023, The Authors. All rights reserved.

关键词： Cells

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Evolution of 14-connected Zr₆ Secondary Building Units through Postsynthetic Linker Incorporation (Jun, 10.1021/acsami.1c07701, 2021)

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ACS APPLIED materials & INTERFACES 2021年第33期13卷 40155-40155页

作者： Hurlock, Matthew J. Hao, Leiduan Kriegsman, Kyle W. Guo, Xiaofeng O'Keeffe, Michael Zhang, Qiang Department of Chemistry Washington State University Pullman Washington 99164 United States Department of Chemistry Materials Science and Engineering Program Washington State University Pullman Washington 99164 United States School of Molecular Sciences Arizona State University Tempe Arizona 85287 United States

Two new zirconium MOFs, WSU-6 and WSU-7, were synthesized through postsynthetic modifications. In both cases, linker insertion was conducted on a MOF consisting of eight-connected (8-c) Zr6 cluster and four-connected (4-c) ETTC linker, WSU-5, which possesses the uncommon 4, 8-c scu-c topology. The insertion of 1, 4-benzenedicarboxylate into the MOF formed the new 4, 12-c mjh topology, WSU-6. Interestingly, when 2, 6-naphthalenedicarboxylate was inserted, WSU-7 can be formed, which possesses a new 4, 14-c jkz topology. WSU-7 contains very rare 14-c Zr6 secondary building units (SBUs) and is the first MOF to have a Zr6 SBUs with connectivity greater than 12. The three Zr-MOFs were structurally characterized, and the photoluminescence properties of the materials were also studied.

关键词： metal−organic frameworks postsynthetic ligand insertion new topology 14-connected Zr6 SBU luminescence

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Microarchitectural Design Variation of the Echinoid Skeleton: A 3D Structural and Mechanical Study of Paracentrotud lividusi

SSRN

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SSRN 2024年

作者： Perricone, Valentina Cesarano, Pasquale Deb, Mainak Lublin, Derek Mutalipassi, Mirko Pappalardo, Lucia Kisailus, David Marmo, Francesco Department of Materials Science and Engineering University of California Irvine United States Department of Structures for Engineering and Architecture University of Naples Federico II Italy Materials and Manufacturing Technology Program University of California Irvine United States Department of Integrative Marine Ecology Stazione Zoologica Anton Dohrn Villa Comunale Napoli Italy Palermo Italy Italy Wipro Technologies

Biological materials usually show remarkable mechanical properties, despite being composed of fragile and simple components (i.e., strong but brittle minerals and tough but weak proteins). These properties are conferred through a multiscale design, in which shapes, structures and composition are coherently organized leading to unique emerging strategies. Noteworthy is the case of the sea urchin skeleton, a hierarchical tasseled structure composed of multiple calcitic plates that are both lightweight and load-bearing. At the microscale, each plate shows a unique species-specific pattern consisting of a porous 3D lattice-like meshwork of trabeculae, called stereom. Interestingly, the stereom architecture is extremely complex and variable in different basic types, each one characterized by a unique topology and structural behaviors. In this context, the present study provides an in-depth analysis of the microarchitectural variability in the sea urchin Paracentrotus lividus. Accordingly, micro-CT scans, image analysis, 3D modeling, and linear elastic FE-Analysis were conducted to provide new insights about the topological and geometrical variability of the different stereom types, and their region-specific mechanical behavior calculated for tensile and shear loading. These results are of value to ameliorate the understanding of the mechanical function of the stereom variability, as well as to identify adaptive solutions useful for future biomimetic transfer applications. © 2024, The Authors. All rights reserved.

关键词： Finite element method

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Impact of Quantum Well Thickness on Efficiency Loss in InGaN/GaN LEDs: Challenges for Thin-Well Designs

arXiv

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arXiv 2025年

作者： Li, Xuefeng Pant, Nick Rahman, Sheikh Ifatur Armitage, Rob Rajan, Siddharth Kioupakis, Emmanouil Feezell, Daniel University of New Mexico AlbuquerqueNM87106 United States Department of Materials Science & Engineering University of Michigan Ann ArborMI48109 United States Applied Physics Program University of Michigan Ann ArborMI48109 United States Department of Electrical and Computer Engineering The Ohio State University ColumbusOH43210 United States Lumileds LLC San JoseCA95131 United States Department of Materials Science and Engineering The Ohio State University ColumbusOH43210 United States

We investigate the impact of quantum well (QW) thickness on efficiency loss in c-plane InGaN/GaN LEDs using a small-signal electroluminescence (SSEL) technique. Multiple mechanisms related to efficiency loss are independently examined, including injection efficiency, carrier density vs. current density relationship, phase space filling (PSF), quantum confined stark effect (QCSE), and Coulomb enhancement. An optimal QW thickness of around 2.7 nm in these InGaN/GaN LEDs was determined for quantum wells having constant In composition. Despite better control of deep-level defects and lower carrier density at a given current density, LEDs with thin QWs still suffer from an imbalance of enhancement effects on the radiative and intrinsic Auger-Meitner recombination coefficients. The imbalance of enhancement effects results in a decline in internal quantum efficiency (IQE) and radiative efficiency with decreasing QW thickness at low current density in LEDs with QW thicknesses below 2.7 nm. We also investigate how LED modulation bandwidth varies with quantum well thickness, identifying the key trends and their implications for device performance. Copyright © 2025, The Authors. All rights reserved.

关键词： Semiconductor quantum wells

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Machine Learning-Enhanced Design of Lead-Free Halide Perovskite materials Using Density Functional Theory

arXiv

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arXiv 2024年

作者： Kumar, Upendra Kim, Hyeon Woo Maurya, Gyanendra Kumar Raj, Bincy Babu Singh, Sobhit Kushwaha, Ajay Kumar Cho, Sung Beom Ko, Hyunseok Jinju52851 Korea Republic of Department of Materials Science and Engineering Hanyang University Seoul04763 Korea Republic of Department of Physics GLA University Mathura281406 India School of Material Science and Engineering Pusan National University 2 Busandaehak-ro 63beon-gil Geumjeong-gu Busan46241 Korea Republic of Department of Mechanical Engineering The University of Rochester New York14611 United States Materials Science Program University of Rochester RochesterNY14627 United States Department of Metallurgy Engineering and Materials Science Indian Institute of Technology Indore Khandwa Road Simrol Indore453552 India Department of Energy Systems Research Ajou University Suwon16499 Korea Republic of

The investigation of emerging non-toxic perovskite materials has been undertaken to advance the fabrication of environmentally sustainable lead-free perovskite solar cells. This study introduces a machine learning methodology aimed at predicting innovative halide perovskite materials that hold promise for use in photovoltaic applications. The seven newly predicted materials are as follows: CsMnCl4, Rb3Mn2Cl9, Rb4MnCl6, Rb3MnCl5, RbMn2Cl7, RbMn4Cl9, and CsIn2Cl7. The predicted compounds are first screened using a machine learning approach, and their validity is subsequently verified through density functional theory calculations. CsMnCl4 is notable among them, displaying a bandgap of 1.37 eV, falling within the Shockley-Queisser limit, making it suitable for photovoltaic applications. Through the integration of machine learning and density functional theory, this study presents a methodology that is more effective and thorough for the discovery and design of materials. © 2024, CC BY.

关键词： Density functional theory

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Thermoelectrically Elevated Hydrogel Evaporation for Personal Cooling under Extreme Heat

arXiv

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arXiv 2025年

作者： Pei, Yu Feng, Tianshi Chambers, Robert Cai, Shengqiang Chen, Renkun Department of Mechanical and Aerospace Engineering University of California San Diego 9500 Gilman Drive La Jolla CA92093 United States Materials Science and Engineering Program University of California San Diego 9500 Gilman Drive La Jolla CA92093 United States

Extreme heat events with wet-bulb temperatures (WBT) above 35°C pose serious risks to human survival, and conventional hydrogel evaporative cooling alone may not provide sufficient relief as it must be maintained at a sufficiently high temperature to achieve effective evaporation in hot, humid conditions. This study integrates thermoelectric devices (TEDs) with hydrogels to create an effective personal cooling solution. TEDs pump heat away from the skin to maintain comfort while simultaneously increasing the hydrogel’s temperature to enhance evaporation. This hybrid system outperforms TEDs or hydrogel alone in extreme conditions (temperature up to 55°C and relative humidity up to 88%, with WBT > 35°C) and can operate for over six hours with a manageable hydrogel and battery weight. The active temperature control of TEDs allows adaptation to changing thermal loads and environments. These results demonstrate the potential of hybrid evaporative and thermoelectric cooling as an efficient, adaptable, and sustainable personal cooling solution to combat extreme heat. Copyright © 2025, The Authors. All rights reserved.

关键词： Evaporative cooling systems

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Direct observation of structural phase transformations during continuous phosphorus deposition on Cu(111)

arXiv

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arXiv 2024年

作者： David, Jiří Jeřábek, František Procházka, Pavel Černý, Miroslav Ciobanu, Cristian V. Průša, Stanislav Šikola, Tomáš Kodambaka, Suneel Kolíbal, Miroslav Institute of Physical Engineering Brno University of Technology Technická 2 Brno616 69 Czech Republic CEITEC BUT. Brno University of Technology Purkyňova 123 Brno612 00 Czech Republic Department of Mechanical Engineering Materials Science Program Colorado School of Mines GoldenCO80401 United States Department of Materials Science and Engineering Virginia Polytechnic Institute State University BlacksburgVA24061 United States

Blue phosphorene - two-dimensional, hexagonal-structured, semiconducting phosphorus - has gained attention as it is considered easier to synthesize on metal surfaces than its allotrope, black phosphorene. Recent studies report different structures of phosphorene, for example, on Cu(111), but the underlying mechanisms of their formation are not known. Here, using a combination of in situ ultrahigh vacuum low-energy electron microscopy and in vacuo scanning tunneling microscopy, we determine the time-evolution of the surface structure and morphology during the deposition of phosphorus on single-crystalline Cu(111). We find that during early stages of deposition, phosphorus intermixes with Cu, resulting in copper phosphide structures. With increasing surface concentration of phosphorus, the phosphide phase disappears and a blue phosphorene layer forms, followed by self-assembly of highly ordered phosphorus clusters that eventually grow into multilayer islands. We attribute the unexpected transformation of stable phosphide to a phosphorene layer, and the previously unreported multilayer growth, to the presence of a large concentration of P2 dimers on the surface. Our results constitute direct evidence for a new growth mode leading to a phosphorene layer via an intermediary phase, which could underpin the growth of other 2D materials on strongly interacting substrates. © 2024, CC BY-SA.

关键词： Self assembly

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New Insights into the Effects of Solidification Process on The Thermodynamic Parameters and Mechanical Properties of Cualbenbni Shape Memory Alloy

SSRN

引用

SSRN 2023年

作者： Silva, David D.S. Vieira, Rafael T. Falcão, Gabriely M.S. Brito, Ieverton C.A. Caluête, Rafael E. Gomes, Rodinei M. Oliveira, Danniel F. Federal University of São Carlos Graduate Program in Materials Science and Engineering SP São Carlos13565-905 Brazil Colorado School of Mines George S. Ansell Department of Metallurgical and Materials Engineering GoldenCO80401 United States Federal University of Paraíba Graduate Program in Materials Science and Engineering PB João Pessoa58051-900 Brazil Federal University of Paraíba Department of Materials Engineering PB João Pessoa58051-900 Brazil Federal University of Paraíba Department of Mechanical Engineering PB João Pessoa58051-900 Brazil

In this work, the influence of the solidification process on the microstructure, thermodynamic parameters and mechanical properties of CuAlBeNbNi shape memory alloy (SMA) was investigated. While directional solidification has been used to improve functional properties in Cu-based SMAs, the squeeze casting process has not yet been explored. The results indicate that the processes of unidirectional solidification and squeeze casting offer an alternative method to modify the thermodynamic parameters, mechanical properties, and microstructural properties of the CuAlBeNbNi SMA while keeping the composition constant. This study aims to fill the knowledge gap regarding the impact of solidification processes on the properties of Cu-based SMAs, specifically investigating CuAlBeNbNi SMAs. © 2023, The Authors. All rights reserved.

关键词： Microstructural evolution

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