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FePd Single Layer and Synthetic Antiferromagnet with Low Damping and Crystalline Perpendicular Magnetic Anisotropy on Amorphous Si/SiO2 Wafers

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FePd Single Layer and Synthetic Antiferromagnet with Low Dam...

Magnetic Conference - Short Papers (INTERMAG Short Papers), IEEE International

作者： Deyuan Lyu Jenae E. Shoup Dingbin Huang Xiaojia Wang Daniel B. Gopman Jian-Ping Wang Department of Electrical and Computer Engineering University of Minnesota Minneapolis Minnesota USA Materials Science and Engineering Division National Institute of Standards and Technology Gaithersburg Maryland USA Department of Mechanical Engineering University of Minnesota Minneapolis Minnesota USA

(001)-textured L1 0 -phase FePd possesses strong crystalline perpendicular magnetic anisotropy (PMA) and low Gilbert damping constant and thus, is considered a promising material choice for scalable spintronic devices. To date, however, well-textured L1 0 -FePd(001) thin films can only be prepared on a few expensive substrates, which directly impedes their industry compatibility and application prospect. In this digest, we report the deposition of L1 0 -FePd(001) single layer and synthetic antiferromagnet (SAF) on industry-ready Si/SiO 2 wafers with large PMA, low damping, and strong antiferromagnetic interlayer exchange coupling. The microstructures of L1 0 -FePd(001) single layer and SAF were imaged using scanning transmission electron microscopy. We observed sharp and flat interfaces between each layer as well as the heteroepitaxial growth of sample stacks, which explains the high performance of the samples.

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Textual Training for the Hassle-Free Removal of Unwanted Visual Data: Case Studies on OOD and Hateful Image Detection

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arXiv 2024年

作者： Lee, Saehyung Mok, Jisoo Park, Sangha Shin, Yongho Jung, Dahuin Yoon, Sungroh Department of Electrical and Computer Engineering Seoul National University Korea Republic of Qualcomm Korea YH Seoul Korea Republic of School of Computer Science and Engineering Soongsil University Korea Republic of Interdisciplinary Program in Artificial Intelligence Seoul National University Korea Republic of

In our study, we explore methods for detecting unwanted content lurking in visual datasets. We provide a theoretical analysis demonstrating that a model capable of successfully partitioning visual data can be obtained using only textual data. Based on the analysis, we propose Hassle-Free Textual Training (HFTT), a streamlined method capable of acquiring detectors for unwanted visual content, using only synthetic textual data in conjunction with pre-trained vision-language models. HFTT features an innovative objective function that significantly reduces the necessity for human involvement in data annotation. Furthermore, HFTT employs a clever textual data synthesis method, effectively emulating the integration of unknown visual data distribution into the training process at no extra cost. The unique characteristics of HFTT extend its utility beyond traditional out-of-distribution detection, making it applicable to tasks that address more abstract concepts. We complement our analyses with experiments in out-of-distribution detection and hateful image detection. Our codes are available at https://***/Saehyung-Lee/HFTT © 2024, CC BY.

关键词： Data assimilation

electrical Characteristics of in situ Mg-doped β-Ga2O3 Current-Blocking Layer for Vertical Devices

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arXiv 2023年

作者： Saha, Sudipto Meng, Lingyu Bhuiyan, A.F.M. Anhar Uddin Sharma, Ankit Saha, Chinmoy Nath Zhao, Hongping Singisetti, Uttam Electrical Engineering Department University at Buffalo BuffaloNY14260 United States Department of Electrical and Computer Engineering The Ohio State University ColumbusOH43016 United States Department of Materials Science and Engineering The Ohio State University ColumbusOH43016 United States

The lack of p-type doping has impeded the development of vertical gallium oxide (Ga2O3) devices. Current blocking layers (CBL) using implanted deep acceptors has been used to demonstrate vertical devices. This paper presents the first demonstration of in situ Mg-doped β- Ga2O3 CBLs grown using metalorganic chemical vapor deposition. Device structures were designed with in-situ Mg doped layers with varied targeted Mg doping concentrations, which were calibrated by quantitative secondary ion mass spectroscopy (SIMS). The effectiveness of the CBL is characterized using temperature dependent current-voltage measurements using n-Mg-doped-n structures, providing crucial insight into the underlying mechanisms. To further validate the experimental results, a TCAD simulation is performed and the electrically active effective doping is found to be dependent on the Mg-doping density, offering a new perspective on the optimization of CBL performance. Breakdown measurements show a 3.4 MV/cm field strength. This study represents a significant step forward in the development of Ga2O3-based devices and paves the way for future advancements in this exciting field. © 2023, CC BY-NC-SA.

关键词： Gallium compounds

Chiral, Topological, and Knotted Colloids in Liquid Crystals

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arXiv 2024年

作者： Yuan, Ye Smalyukh, Ivan I. Hiroshima University Hiroshima Higashi-Hiroshima739-8526 Japan Department of Physics Department of Electrical Computer and Energy Engineering Materials Science and Engineering Program Soft Materials Research Center University of Colorado BoulderCO80309 United States Renewable and Sustainable Energy Institute National Renewable Energy Laboratory University of Colorado BoulderCO80309 United States

The geometric shape, symmetry, and topology of colloidal particles often allow for controlling colloidal phase behavior and physical properties of these soft matter systems. In liquid crystalline dispersions, colloidal particles with low symmetry and nontrivial topology of surface confinement are of particular interest, including surfaces shaped as handlebodies, spirals, knots, multi-component links, and so on. These types of colloidal surfaces induce topologically nontrivial three-dimensional director field configurations and topological defects. Director switching by electric fields, laser tweezing of defects, and local photo-thermal melting of the liquid crystal host medium promote transformations among many stable and metastable particle-induced director configurations that can be revealed by means of direct label-free three-dimensional nonlinear optical imaging. The interplay between topologies of colloidal surfaces, director fields, and defects is found to show a number of unexpected features, such as knotting and linking of line defects, often uniquely arising from the nonpolar nature of the nematic director field. This review article highlights fascinating examples of new physical behavior arising from the interplay of nematic molecular order and both chiral symmetry and topology of colloidal inclusions within the nematic host. Furthermore, the article concludes with a brief discussion of how these findings may lay the groundwork for new types of topology-dictated self-assembly in soft condensed matter leading to novel mesostructured composite materials, as well as for experimental insights into the pure-math aspects of low-dimensional topology. © 2024, CC BY.

关键词： Crystal symmetry

Morphological investigation and pH sensing properties of β-Ga₂O₃ EGFET-pH sensor

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materials science and engineering: B 2024年 300卷

作者： Yadlapalli, Bharath Kumar Chou, Hsin-Yu Chiang, Jung-Lung Wuu, Dong-Sing Department of Materials Science and Engineering National Chung Hsing University Taichung 40227 Taiwan Prospective Technology of Electrical Engineering and Computer Science National Chin-Yi University of Technology Taichung 411030 Taiwan Department of Applied Materials and Optoelectronic Engineering National Chi Nan University Nantou 54561 Taiwan

In our study, β-Ga2O3 particles of various morphologies deposited on FTO glass substrates through hydrothermal method under different pH conditions and pre-stirring temperatures. The particles examined using XRD, FES... 详细信息

In our study, β-Ga₂O₃ particles of various morphologies deposited on FTO glass substrates through hydrothermal method under different pH conditions and pre-stirring temperatures. The particles examined using XRD, FESEM, FTIR and Raman spectroscopy instruments. These results showed that the β-Ga₂O₃ microrods prepared with pH = 3.15 solution at different pre-stirring temperatures followed by hydrothermal reaction had several crystalline orientations ([−4 0 1], [0 0 2], [4 0 3]). The FTIR and Raman spectra measurements confirmed the existence of Ga[sbnd]O[sbnd]Ga and Ga[sbnd]OH bending modes. In the range of pH = 3–11, the EGFET-pH sensor prepared with β-Ga₂O₃ microrods shown a high current-pH sensitivity of 0.541 (mA)^1/2/pH with a linearity of 97.83 % and a high voltage-pH sensitivity of 73.99 mV/pH with linearity of 96.85 %. These results suggest that β-Ga₂O₃ microrods have pH sensitivity higher than the ideal Nernstian response. This confirms the use of β-Ga₂O₃ microrods as a sensing membrane in high-performance pH sensors or biosensors. © 2023 Elsevier B.V.

关键词： EGFET-pH sensor Hydrothermal deposition β-Ga2O3/FTO β-gallium oxide

Meta-optic accelerators for object classifier

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Meta-optic accelerators for object classifier

Conference on Lasers and Electro-Optics (CLEO)

作者： Hanyu Zheng Quan Liu You Zhou Ivan I. Kravchenko Yuankai Huo Jason Valentine Department of Electrical and Computer Engineering Vanderbilt University Nashville TN USA Department of Computer Science Vanderbilt University Nashville TN USA Interdisciplinary Materials Science Program Vanderbilt University Nashville TN USA Center for Nanophase Materials Sciences Oak Ridge National Laboratory Oak Ridge TN USA Department of Mechanical Engineering Vanderbilt University Nashville TN USA

A meta-optic platform for accelerating object classification is demonstrated. End-to-end design is used to co-optimize the optical and digital systems resulting in a high-speed and robust classifier with 93.1% accurac... 详细信息

ISBN: (纸本)9781957171258

关键词： Image analysis Image resolution Machine vision Neural networks Optical systems Signal processing

Bonding and Failure Mechanisms of Sintered-silver Die-attach on Electroless Nickel (Phosphorus) Surface Finish for Packaging Power Electronics Modules

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IEEE Transactions on Power Electronics 2024年

作者： Wang, Meiyu Zhang, Haobo Hu, Weibo Mei, Yunhui Lu, Guo-Quan Nankai University College of Electronic Information and Optical Engineering Tianjin300350 China Shenzhen research institute of Nankai University Shenzhen518083 China Nankai University Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology Tianjin300350 China Tiangong University School of Electrical Engineering Tianjin300387 China The Bradley Department of Electrical and Computer Engineering The Department of Materials Science and Engineering BlacksburgVA24061 United States

The low-temperature silver sintering technology has been increasingly applied for die-attach in power electronics modules. Most reported studies of the technology involved bonding on silver (Ag) or gold (Au) surface finish. Compared to Ag or Au, electroless nickel (phosphorus) or Ni(P) is a cost-effective and widely-used process for surface-finishing module substrates. However, there is a lack of studies on sintered-Ag bonding on the Ni(P) surface. In this study, IGBT devices were bonded using pressureless Ag-sintering on electroless Ni(P)-plated substrates. Micro-morphologies and macro-properties were then characterized before and after three reliability tests including high temperature storage life (HTSL), steady-state temperature-humidity bias life (STHBL), and temperature cycling (TC) tests. The as-sintered joints measured strong adhesion of 39 MPa, resulting from Ag-NiO-Ni chemical bonds across the (111) crystal planes with reduced lattice misfit. The Ag-Ni(P) joints exhibited high reliability under high-temperature and thermo-mechanical stress in the HTSL and TC tests, but performed poorly when exposed to high humidity in the STHBL test. The founding in this study helps understand the physical nature of bonding between sintered-Ag and Ni(P), and its failure mechanisms under the influence of different physical stresses. © 1986-2012 IEEE.

关键词： Bond strength (chemical)

Evolution-Assisted Deep Reinforcement Learning for Fast Charging Station Coordinated Operation 13

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Evolution-Assisted Deep Reinforcement Learning for Fast Char...

13th IEEE Congress on Evolutionary Computation, CEC 2024

作者： Yang, Xiaoying Gu, Yujing Jia, Fuhua Li, Yiran Wang, Hongru Du, Nanjiang Cui, Tianxiang Ye, Yujian Bai, Ruibin State Grid Nantong Power Supply Company Nantong China University of Nottingham Ningbo China Department of Mechanical Materials and Manufacturing Engineering Ningbo China School of Electrical Engineering Southeast University Nanjing China School of Computer Science University of Nottingham Ningbo China Ningbo China University of Nottingham Ningbo China The Digital Port Technologies Lab Ningbo China Nottingham Ningbo China Beacons of Excellence Research and Innovation Institute Ningbo China

ISBN: (纸本)9798350308365

The shift towards transportation electrification, marked by the rising use of electric vehicles (EVs) and the development of fast charging stations (FCS), plays a crucial role in transport decarbonization initiatives. To optimize the rollout of FCS and set appropriate charging service fees (CSF)-a process referred to as the coupled FCS multi-stage bi-level operation problem (FCS-MBOP)-is essential for improving both investment and operational efficiency within the integrated power distribution and transportation network (CPTN). For operators, it's not only necessary to adapt to short-term fluctuations within the environment but also to swiftly respond to changes in the FCS layout resulting from various long-term investment decisions. To address this complexity, we introduce a dual-timescale evolutionary assist deep reinforcement learning framework, which includes two specialized agents with distinct functions: an investment agent (planner) and an operational agent (operator). The planner focuses on annual investments, evolving long-term strategies that weigh social benefits against investment costs through the use of a genetic algorithm (GA). In contrast, the operator acts on an hourly basis, fine-tuning CSF to alleviate traffic congestion and minimize the social costs, while taking into account the planner's feasible investment decisions. Leveraging the integrated capabilities of a graph neural network (GNN), long-short-term memory (LSTM), and attention mechanisms, our framework's agents are adept at extracting both temporal and spatial features and facilitating the transfer of experiences across different investment stages. Empirical evidence underscores the effectiveness of our approach, showcasing its ability to surpass conventional methodologies in delivering high-quality solutions. © 2024 IEEE.

关键词： Deep reinforcement learning

Moiré polar vortex, flat bands and Lieb lattice in twisted bilayer BaTiO3

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arXiv 2024年

作者： Lee, Seungjun de Sousa, D.J.P. Jalan, Bharat Low, Tony Department of Electrical and Computer Engineering University of Minnesota MinneapolisMN55455 United States Department of Chemical Engineering and Materials Science University of Minnesota MinneapolisMN55455 United States Department of Physics University of Minnesota MinneapolisMN55455 United States

Advances in material fabrication techniques and growth methods have opened up a new chapter for twistronics, in the form of twisted freestanding three-dimensional material membranes. Through first-principles calculations based on density functional theory, we investigate the crystal and electronic structures of twisted bilayer BaTiO3. Our findings reveal that large stacking fault energy leads to chiral in-plane vortex pattern that was recently observed in experiments. Moreover, we also found non-zero out-of-plane local dipole moments, indicating that the strong interlayer interaction might offer promising strategy to stabilize ferroelectric order in the two-dimensional limit. Remarkably, the vortex pattern in the twisted BaTiO3 bilayer support localized electronic states with quasi-flat bands, associated with the interlayer hybridization of oxygen pz orbitals. We found that the associated band width reaches a minimum at ∼19◦ twisting, configuring the largest magic angle in moiré systems reported so far. Further, the moiré vortex pattern bears a striking resemblance to two interpenetrating Lieb lattices and corresponding tight-binding model provides a comprehensive description of the evolution the moiré bands with twist angle and reveals the topological nature of these states. © 2024, CC BY.

关键词： Density functional theory