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Emergent magnetic phases and piezomagnetic effects in MnxNi1−xF2 thin film alloys

Physical Review B 2023年第13期108卷 134437-134437页

作者： Ryan Van Haren Nessa Hald David Lederman Department of Physics University of California Santa Cruz Santa Cruz California 95064 USA Materials Science and Engineering Program School for Engineering of Energy Matter and Transport Arizona State University Tempe Arizona 85287 USA

The effect of random competing single-ion anisotropies in antiferromagnets was studied using epitaxial MnxNi1−xF2 antiferromagnetic thin film alloys grown via molecular beam epitaxy. The crystal structure of this material is tetragonal for all values of x, and the Mn sites have a magnetic easy-axis single-ion anisotropy while the Ni sites have an easy-plane anisotropy perpendicular to the Mn easy axis. Crystallographic and magnetization measurements demonstrated that the thin film alloys were homogeneously mixed and did not phase separate into their constituent parts. Pure MnF2 thin films epitaxially grown on MgF2 exhibited compressive strain along all three crystallographic axes which resulted in piezomagnetic effects. The piezomagnetism disappeared if the film was grown on a (MnNi)F2 graded buffer layer. A mean-field theory fit to the transition temperature as a function of the Mn concentration x, which takes into account piezomagnetic effects, gave a magnetic exchange constant between Mn and Ni ions of JMnNi=0.305±0.003meV. Mean-field theory calculations also predicted the existence of an oblique antiferromagnetic phase in the MnxNi1−xF2 alloy which agreed with the experimental data. A magnetic phase diagram for MnxNi1−xF2 thin film alloys was constructed and showed evidence for the existence of two unique magnetic phases, in addition to the ordinary antiferromagnetic and paramagnetic phases: an oblique antiferromagnetic phase, and an emergent magnetic phase proposed to be either a magnetic glassy phase or a helical phase. The phase diagram is quantitatively different from that of FexNi1−xF2 because of the much larger single-ion anisotropy of Fe2+ compared to Mn2+.

关键词： Epitaxial strain Magnetic anisotropy Magnetic interactions Magnetic phase transitions Magnetism Alloys Antiferromagnets Magnetic thin films Solid solutions Thin films Crystallography Mean field theory Molecular beam epitaxy Susceptibility measurements X-ray diffraction

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PET-derived bis(2-hydroxyethyl) terephthalate as a new linker source for solvent-free and hydrothermal synthesis of BDC-based MOFs

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materials Today Nano 2024年 25卷

作者： Krisbiantoro, Philip Anggo Kuo, Tzu-Jung Chang, Yu-Chia Liao, Weisheng Sun, Jih-Peng Yang, Chun-Yen Kamiya, Yuichi Shieh, Fa-Kuen Chen, Chia-Chin Wu, Kevin C.-W Molecular Science and Technology Program Taiwan International Graduate Program Academia Sinica Taipei11529 Taiwan International Graduate Program of Molecular Science and Technology National Taiwan University Taipei10617 Taiwan Department of Chemical Engineering National Taiwan University Taipei10617 Taiwan Faculty of Environmental Earth Science Hokkaido University Nishi 5 Kita 10 Kita-ku Sapporo060-0810 Japan Department of Chemistry National Central University Taoyuan32001 Taiwan Center of Atomic Initiative for New Materials National Taiwan University Taipei10617 Taiwan Department of Chemical Engineering and Materials Science Yuan Ze University Chung-Li Taoyuan Taiwan

To date, the high cost of organic linkers and the energy-consuming synthesis processes remain two of the main challenges for the commercialization of metal-organic frameworks (MOFs). Herein, we demonstrate that polyethylene terephthalate (PET)-derived bis(2-hydroxyethyl) terephthalate (BHET) is a new linker source that enables the facile solvent-free and hydrothermal synthesis of BDC-based MOFs. Using BHET as a linker source, UiO-66(Zr) was rapidly synthesized via a solvent-free "grind and bake" technique, while Ca-BDC and Ba-BDC were easily obtained by using hydrothermal synthesis. We found that the hydrolysis of BHET to terephthalate anion (BDC2−) over proton produced from the hydrolysis/clustering of Zr precursor and hydroxyl anion produced from the dissolution of M(OH)2 (M = Ca or Ba) was the key to the crystal growth of solvent-free synthesized UiO-66(Zr) and hydrothermally synthesized M-BDC (M = Ca or Ba), respectively. While the as-synthesized UiO-66(Zr) was highly active for the esterification of lactic acid (LA) with ethanol (EtOH), Ca-BDC and Ba-BDC exhibited remarkable electrochemical performance for lithium storage. Our strategy provides a major step towards realizing the idea of a more facile, green, and low-cost synthesis of PET-derived MOFs compared to prior arts applicable for catalysis and energy applications. © 2024

关键词： Lithium-ion batteries

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Synergetic effects of multiple junction and surface hydroxyl in Cu/CuO/Cu2O/TiO2 heterostructures towards highly efficient photocatalysts for hydrogen generation

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materials science for Energy Technologies 2025年 8卷 131-142页

作者： Subagyo, Riki Anindika, Garcelina Rizky Aufkani, Afif Akmal Zhang, Lei Ardhyananta, Hosta Burhan, R.Y. Perry Nugraheni, Zjahra Vianita Akhlus, Syafsir Bahruji, Hasliza Prasetyoko, Didik Wellia, Diana Vanda Ivansyah, Atthar Luqman Arramel Kusumawati, Yuly Department of Chemistry Faculty of Science and Analytic Data Institut Teknologi Sepuluh Nopember Surabaya60111 Indonesia Center of Excellence Applied Physics and Chemistry Nano Center Indonesia Jl PUSPIPTEK South Tangerang Banten15314 Indonesia Department of Physics National University of Singapore Singapore117551 Singapore Department of Materials and Metallurgical Engineering Faculty of Industrial Technology and Systems Engineering Institut Teknologi Sepuluh Nopember Surabaya60111 Indonesia Centre of Advanced Material and Energy Science Universiti Brunei Darussalam Jalan Tungku Link BE 1410 Brunei Department of Chemistry Faculty of Mathematics and Natural Sciences Universitas Andalas Padang25163 Indonesia Master Program in Computational Science Faculty of Mathematics and Natural Science Institut Teknologi Bandung Jalan Ganesha No. 10 Bandung40132 Indonesia Instrumentation and Computational Physics Research Group Department of Physics Faculty of Mathematics and Natural Sciences Institut Teknologi Bandung Jalan Ganesha No.10 West Java Bandung40132 Indonesia

The implementation of titanium dioxide (TiO2) as a photocatalyst material in hydrogen (H2) evolution reaction (HER) has embarked renewed interest in the past decade. Rapid electron-hole pairs recombination and wide band gap of a photo-sensitive material of TiO2 are detrimental toward the targeted catalytical reaction. In this study, we present the rational design, fabrication, photocatalytic performance of TiO2-Cu/CuO/Cu2O heterostructures (CuTi) using viable chemical reduction method. The Z-scheme and S-scheme are succesfully generated across the TiO2/CuO/Cu2O interfaces, while the Schottky junction arises on the Cu perimeters. This is evidenced from the blue shifted about 0.3 eV of Cu 2p core level determined by using X-ray photoemission spectroscopy (XPS), in combination with the formation of inverse V-shape of the Mott-Schottky plots. In addition, we find that Cu/CuO/Cu2O facilitates photon absorption range up to the visible region. The multiple heterojunction and the large number of OHsurface enhanced charge carrier transfer are associated to the suppression of photoluminescence (PL) intensity, high surface hydroxyl (OHsurface) density in CuTi probed by XPS, and fast electron transfer based on the electrochemical measurements. The presence of OHsurface inhibits the recombination of electron. A significant H2 photogeneration rate enhancement is achieved when an optimized 5 wt% Cu/CuO/Cu2O concentration is used on TiO2 to achieve 7,157.19 μmol·g−1 (1,789.30 μmol·g−1·h−1). Based on this finding, zero emission energy innitiative could be materialized under multiple heterojunctions in photocatalytic process is beneficial for enhancing the H2 production. © 2025 The Authors

关键词： Titanium dioxide

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Process Optimization and Scaling of Molybdenum and Tungsten in Additive Manufacturing Techniques

SSRN

引用

SSRN 2024年

作者： Islam, Zahabul Kunkel, William Hatler, Caleb Thoma, Dan J. Mechanical and Manufacturing Engineering Program School of Engineering Bowling Green State University Bowling GreenOH43403 United States Alloy Design and Development Laboratory Department of Materials Science and Engineering University of Wisconsin MadisonWI53706 United States

Metal additive manufacturing processes pose a daunting challenge in defining optimal process parameters that yield porosity defect-free, dense parts. This is particularly true in refractory metals, where high melting temperatures limit process parameter windows. This present study investigates a dimensionless number analysis that has been derived through the Buckingham-PI theorem and demonstrates a robust correlation between process parameters and the density of the fabricated components. The introduction of this dimensionless number enables the initial estimation of process parameters without extensive modeling or experimentation. Additionally, a universal scaling law is proposed to enhance the translation of predicting process parameters for achieving an optimal density in as-built parts between different processing techniques. A combination of this proposed dimensionless number and scaling law offers process maps for tungsten and molybdenum with previously unknown process parameters. The universality of the proposed dimensionless number also demonstrates transferability, enabling the prediction of process parameters both for laser powder bed fusion and directed energy deposition systems. © 2024, The Authors. All rights reserved.

关键词： 3D printing

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Techno-economic and life-cycle assessment of electrochemical captured CO2 conversion process in monoethanolamine

Techno-economic and life-cycle assessment of electrochemical...

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2022 AIChE Annual Meeting

作者： Lee, Suhyun Choi, Woong Kim, Jae Hyung Hwang, Yun Jeong Na, Jonggeol Ewha Womans University School of Chemical Engineering and Materials Science Korea Republic of Ewha Womans University Graduate program in System Health Science and Engineering Korea Republic of Clean Energy Research Center Korea Institute of Science and Technology Korea Republic of Seoul National University School of Chemistry Korea Republic of Korea Republic of Ewha Womans University Dept. of Chemical Engineering & Material science Advanced Manufacturing Systems Laboratory Korea Republic of

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A Data-driven Framework to Accelerate the Discovery of Hybrid Cathode materials for Metal-based Batteries

arXiv

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arXiv 2024年

作者： Biby, Ahmed H. Rich, Benjamin S. Musgrave, Charles B. Materials Science and Engineering Program University of Colorado Boulder BoulderCO80309 United States Department of Chemistry University of Colorado Boulder BoulderCO80309 United States Department of Chemical Engineering University of Utah Salt Lake CityUT84112 United States Department of Materials Science and Engineering University of Utah Salt Lake CityUT84112 United States

Selecting materials for hybrid cathodes for batteries, which involve a combination of intercalation and conversion materials, has gained interest due to their combined synergistic and compromised properties that are not attainable by their homogeneous counterparts. Herein, we present a data-driven, chemistry-agnostic, and inverse material design framework for discovering hybrid cathode materials (HCMs) for metal-based batteries. This framework systematically explores the potential materials space for any given working ion, evaluates the candidate’s stability, and identifies the growth modes/adsorption of the components for a stable hybrid cathode. To demonstrate the application of the framework and its various possible outcomes, we performed a case study, for which the main design objective was to discover HCMs with an average gravimetric energy density surpassing that of the widely used high energy density NMC333 cathode material. The framework identified LiCr4GaS8-Li2S as a promising HCM that achieves an average energy density of 1,424 Wh/kg (on a lithiated cathode basis) that exceeds NMC333’s maximum theoretical energy density of 1,028 Wh/kg. The identified material has several additional desirable features: 1) possession of thermodynamically stable lithiated and delithiated intercalation and conversion phases;2) minimal volume change, upon (de)lithiation, that mitigates the high-volume change of the conversion material;3) high energy density that ameliorates the low energy density of the intercalation material;4) ability of the intercalation component to act as both a conductive additive and immobilizer of S, while simultaneously contributing to the total cathode energy density;5) the intercalation material serves as an ideal support for the soft sulfur species and finally, 6) we anticipate that the life span, self-discharge, mechanical integrity, and capacity fading are better than those of conventional Li-S batteries. The developed framework was instrumental f

关键词： Lithium compounds

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Ytterbium Femtosecond Fiber Laser Ablation Synthesis of Silicon Nanocrystals in Water: Laser Frequency and Pulse Energy Dependence

SSRN

引用

SSRN 2023年

作者： Piatkowski, Piotr A. Ali, Asghar Ialyshev, Vadim Iqbal, Mazhar Alnaser, Ali S. Department of Physics American University of Sharjah Materials Science and Engineering Program College of Arts and Sciences PO Box 26666 Sharjah United Arab Emirates

The utilization of femtosecond laser pulses in synthesizing silicon nanocrystals (SiNCs) poses great potential in producing stable nanostructures with chemically pure surfaces and easy-to- manipulate optical properties. In this work, we present an approach that enhances the production and optical quality of surfactant-free SiNCs synthesized in water by ablating silicon wafer with ytterbium fiber femtosecond laser operating at different pulse energies and repetition rates. By further post-synthesis laser treatment of SiNCs suspensions, fragmentation of larger aggregates is observed leading to absorption broadening and absorption-band blueshift. Furthermore, the increase in the repetition rate, from 1 to 500 kHz, of laser pulses having energies of 20 and 240 mJ leads to a decrease in the Si wafer ablation efficiency from 35 to 1.15 pg/pulse;and from 440 to 5.2 pg/pulse, respectively. Using laser pulses with energy of 240 mJ and a repetition rate of 50 kHz results in maximum SiNCs productivity of 33 mg/h. The dependence of the nanostructures’s size and ablation efficiency on the pulse energy and repetition rate is attributed to thermal effects on the Si/water interface and within the water layer illuminated by the strong laser radiation. © 2023, The Authors. All rights reserved.

关键词： Femtosecond lasers

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Symmetric and isotropic micro/nanorotors driven by a plane-polarized gaussian laser beam 18

Symmetric and isotropic micro/nanorotors driven by a plane-p...

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Optical Trapping and Optical Micromanipulation XVIII 2021

作者： Ding, Hongru Kollipara, Pavana Siddhartha Kotnala, Abhay Chen, Zhihan Zheng, Yuebing Walker Department of Mechanical Engineering University of Texas at Austin AustinTX78712 United States Materials Science and Engineering Program and Texas Materials Institute University of Texas at Austin AustinTX78712 United States

ISBN: (数字)9781510644359

ISBN: (纸本)9781510644342

The flourishing field of light-powered micro/nanorotors provides promising strategies for manufacturing and biomedical needs. However, the torque of optical rotors typically arises from the momentum exchange with photons, which limits the geometries and materials of objects that can be rotated and requires intense laser beams with designed intensity profile and polarization. These factors inhibit the light-powered rotation of highly symmetric or isotropic targets. Herein, we developed an optothermal micro/nanorotors platform that enables the rotation of various colloids with diverse sizes, materials, and various shapes, including live cells and micro/nanoparticles with high symmetry and isotropy. The long-sought-after out-of-plane rotation has been achieved by a single plane-polarized Gaussian laser beam with an ultralow power. This simple rotor approach is foreseen to open new horizons in colloidal and life sciences by offering a non-invasive and universal manipulation. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.

关键词： Rotation

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Periodic phase diagrams in micromagnetics with an eigenvalue solver

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IEEE Transactions on Magnetics 2025年

作者： Ai, Fangzhou Lin, Zhuonan Duan, Jiawei Lomakin, Vitaliy University of California Department of Electrical and Computer Engineering San DiegoCA92093 United States University of California Center for Memory and Recording Research San DiegoCA92093 United States University of California Program in Materials Science and Engineering San Diego92093 United States

This work introduces an approach to compute periodic phase diagram of micromagnetic systems by solving a periodic linearized Landau-Lifshitz-Gilbert (LLG) equation using an eigenvalue solver with the Finite Element Method formalism. The linear operator in the eigenvalue problem is defined as a function of the periodic phase-shift wave vector. The dispersion diagrams are obtained by solving the eigenvalue problem for complex eigenfrequencies and corresponding eigenstates for a range of prescribed wave vectors. The presented approach incorporates a calculation of the periodic effective field, including the exchange and magnetostatic field components. The approach is general in that it allows 3D problems to be handled with any 1D, 2D, and 3D periodicities. The ability to calculate periodic diagrams provides insights into the spin wave propagation and localized resonances in complex micromagnetic structures. © 1965-2012 IEEE.

关键词： Spin waves

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materials Discovery with Extreme Properties via Reinforcement Learning-Guided Combinatorial Chemistry

arXiv

引用

arXiv 2023年

作者： Kim, Hyunseung Choi, Haeyeon Kang, Dongju Lee, Won Bo Na, Jonggeol School of Chemical and Biological Engineering Seoul National University Korea Republic of Department of Chemical Engineering and Materials Science Ewha Womans University Korea Republic of Graduate Program in System Health Science and Engineering Ewha Womans University Korea Republic of

The goal of most materials discovery is to discover materials that are superior to those currently known. Fundamentally, this is close to extrapolation, which is a weak point for most machine learning models that learn the probability distribution of data. Herein, we develop reinforcement learning-guided combinatorial chemistry, which is a rule-based molecular designer driven by trained policy for selecting subsequent molecular fragments to get a target molecule. Since our model has the potential to generate all possible molecular structures that can be obtained from combinations of molecular fragments, unknown molecules with superior properties can be discovered. We theoretically and empirically demonstrate that our model is more suitable for discovering better compounds than probability distribution-learning models. In an experiment aimed at discovering molecules that hit seven extreme target properties, our model discovered 1,315 of all target-hitting molecules and 7,629 of five target-hitting molecules out of 100,000 trials, whereas the probability distribution-learning models failed. Moreover, it has been confirmed that every molecule generated under the binding rules of molecular fragments is 100% chemically valid. To illustrate the performance in actual problems, we also demonstrate that our models work well on two practical applications: discovering protein docking molecules and HIV inhibitors. © 2023, CC BY-NC-SA.

关键词： Probability distributions

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