1
|
Comparison of Ferromagnetic Materials: Past Work, Recent Trends, and Applications. CONDENSED MATTER 2022. [DOI: 10.3390/condmat7010012] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Despite our traditional concept-based understanding of ferromagnetism, an investigation of this phenomenon has revealed several other facts. Ferromagnetism was previously supposed to be exhibited by only a few elements. Subsequently, it was realized that specific elements with d- or f- orbitals demonstrated this phenomenon. When elements without these orbitals exhibited ferromagnetism, intrinsic origin-based and structural defect-based theories were introduced. At present, nonmagnetic oxides, hexaborides of alkaline-earth metals, carbon structures, and nonmetallic non-oxide compounds are gaining significant attention owing to their potential applications in spintronics, electronics, biomedicine, etc. Therefore, herein, previous work, recent trends, and the applications of these materials and studies based on relevant topics, ranging from the traditional understanding of ferromagnetism to the most recent two-element-based systems, are reviewed.
Collapse
|
2
|
Catalytic Activity of High-Surface-Area Amorphous MgO Obtained from Upsalite. Catalysts 2021. [DOI: 10.3390/catal11111338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The first aim of the research was to synthesize a pure Upsalite, which is an amorphous form of MgCO3, by modifying a procedure described in the literature, so that it would be the precursor of a high-surface, amorphous magnesium oxide. The results indicate that within the studied reaction conditions, the type of alcohol used as the reactant has the most pronounced effect on the yield of reaction. From the two alcohols that led to the highest yield of Upsalite, methanol gave a substantially larger surface area (794 vs. 191 m2 g−1). The optimized synthesis conditions of Upsalite were used to obtain MgO via thermolysis, whose activity in the transfer hydrogenation reaction (THR) from ethanol, 2-propanol and 2-pentanol to various carbonyl compounds was determined. The optimal conditions for the thermolysis were as follows: vacuum, T = 673 K as the final temperature, and a heating rate of 2 deg min−1. The high-surface, amorphous magnesia (SBET = 488 m2 g−1) was found to be a very selective catalyst to 4-t-butylcyclohexanone in THR, which led to a diastereoselectivity of over 94% to the E-isomer of 4-t-butylcyclohexanol for more than 3 h, with conversions of up to 97% with either 2-propanol or 2-pentanol as the hydrogen donor. In the case of acrolein and 2-n-propylacrolein being used as the hydrogen acceptors, the unsaturated alcohol (UOL) was the main product of the reaction, with higher UOL yields noted for ethanol than 2-propanol.
Collapse
|
3
|
Davila K, Setlur S, Doermann D, Kota BU, Govindaraju V. Chart Mining: A Survey of Methods for Automated Chart Analysis. IEEE TRANSACTIONS ON PATTERN ANALYSIS AND MACHINE INTELLIGENCE 2021; 43:3799-3819. [PMID: 32365018 DOI: 10.1109/tpami.2020.2992028] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Charts are useful communication tools for the presentation of data in a visually appealing format that facilitates comprehension. There have been many studies dedicated to chart mining, which refers to the process of automatic detection, extraction and analysis of charts to reproduce the tabular data that was originally used to create them. By allowing access to data which might not be available in other formats, chart mining facilitates the creation of many downstream applications. This paper presents a comprehensive survey of approaches across all components of the automated chart mining pipeline, such as (i) automated extraction of charts from documents; (ii) processing of multi-panel charts; (iii) automatic image classifiers to collect chart images at scale; (iv) automated extraction of data from each chart image, for popular chart types as well as selected specialized classes; (v) applications of chart mining; and (vi) datasets for training and evaluation, and the methods that were used to build them. Finally, we summarize the main trends found in the literature and provide pointers to areas for further research in chart mining.
Collapse
|
4
|
Abstract
The study of magnetism in materials without partially filled d or f bands has gained much attention in the past years. Even though it has challenged the understanding of traditional magnetism, there is a wide range of studies debating the nature of magnetism in such materials. Theories on whether the exhibited ferromagnetic behavior is due to sample impurities or intrinsic structural defects have been published throughout the years. Materials such as hexaborides, non-magnetic oxides, and carbon nanostructures have been of great interest due to their potential applications. For a better understanding, herein, we present a literature review combining past and up-to-date studies on these materials.
Collapse
|
5
|
Greenaway AL, Loutris AL, Heinselman KN, Melamed CL, Schnepf RR, Tellekamp MB, Woods-Robinson R, Sherbondy R, Bardgett D, Bauers S, Zakutayev A, Christensen ST, Lany S, Tamboli AC. Combinatorial Synthesis of Magnesium Tin Nitride Semiconductors. J Am Chem Soc 2020; 142:8421-8430. [PMID: 32279492 PMCID: PMC10905991 DOI: 10.1021/jacs.0c02092] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Nitride materials feature strong chemical bonding character that leads to unique crystal structures, but many ternary nitride chemical spaces remain experimentally unexplored. The search for previously undiscovered ternary nitrides is also an opportunity to explore unique materials properties, such as transitions between cation-ordered and -disordered structures, as well as to identify candidate materials for optoelectronic applications. Here, we present a comprehensive experimental study of MgSnN2, an emerging II-IV-N2 compound, for the first time mapping phase composition and crystal structure, and examining its optoelectronic properties computationally and experimentally. We demonstrate combinatorial cosputtering of cation-disordered, wurtzite-type MgSnN2 across a range of cation compositions and temperatures, as well as the unexpected formation of a secondary, rocksalt-type phase of MgSnN2 at Mg-rich compositions and low temperatures. A computational structure search shows that the rocksalt-type phase is substantially metastable (>70 meV/atom) compared to the wurtzite-type ground state. Spectroscopic ellipsometry reveals optical absorption onsets around 2 eV, consistent with band gap tuning via cation disorder. Finally, we demonstrate epitaxial growth of a mixed wurtzite-rocksalt MgSnN2 on GaN, highlighting an opportunity for polymorphic control via epitaxy. Collectively, these findings lay the groundwork for further exploration of MgSnN2 as a model ternary nitride, with controlled polymorphism, and for device applications, enabled by control of optoelectronic properties via cation ordering.
Collapse
Affiliation(s)
- Ann L. Greenaway
- Materials
and Chemistry Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Amanda L. Loutris
- Materials
and Chemistry Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Karen N. Heinselman
- Materials
and Chemistry Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Celeste L. Melamed
- Materials
and Chemistry Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
- Department
of Physics, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Rekha R. Schnepf
- Materials
and Chemistry Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
- Department
of Physics, Colorado School of Mines, Golden, Colorado 80401, United States
| | - M. Brooks Tellekamp
- Materials
and Chemistry Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Rachel Woods-Robinson
- Materials
and Chemistry Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
- Applied
Science and Technology Graduate Group, University
of California at Berkeley, Berkeley, California 94720, United States
- Energy
Technologies Area, Lawrence Berkeley National
Laboratory, Berkeley, California 94702, United States
| | - Rachel Sherbondy
- Materials
and Chemistry Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
- Department
of Metallurgical and Materials Engineering, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Dylan Bardgett
- Materials
and Chemistry Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Sage Bauers
- Materials
and Chemistry Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Andriy Zakutayev
- Materials
and Chemistry Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Steven T. Christensen
- Materials
and Chemistry Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Stephan Lany
- Materials
and Chemistry Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Adele C. Tamboli
- Materials
and Chemistry Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
- Department
of Physics, Colorado School of Mines, Golden, Colorado 80401, United States
| |
Collapse
|
6
|
Pousaneh E, Rüffer T, Assim K, Dzhagan V, Noll J, Zahn DRT, Mertens L, Mehring M, Schulz SE, Lang H. Magnesium β-ketoiminates as CVD precursors for MgO formation. RSC Adv 2018; 8:19668-19678. [PMID: 35540974 PMCID: PMC9080701 DOI: 10.1039/c8ra01851k] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 05/14/2018] [Indexed: 11/21/2022] Open
Abstract
The synthesis and characterization of bis(ketoiminato)magnesium(ii) complexes of composition [Mg(OCR2CH2CHR1NCH2CH2X)2] (X = NMe2: 3a, R1 = R2 = Me; 3b, R1 = Me, R2 = Ph. X = OMe: 3c, R1 = R2 = Me) are reported.
Collapse
|
8
|
Abstract
Magnetism without d-orbital electrons seems to be unrealistic; however, recent observations of magnetism in non-magnetic oxides, such as ZnO, HfO2, and MgO, have opened new avenues in the field of magnetism. Magnetism exhibited by these oxides is known as d° ferromagnetism, as these oxides either have completely filled or unfilled d-/f-orbitals. This magnetism is believed to occur due to polarization induced by p-orbitals. Magnetic polarization in these oxides arises due to vacancies, the excitation of trapped spin in the triplet state. The presence of vacancies at the surface and subsurface also affects the magnetic behavior of these oxides. In the present review, origins of magnetism in magnesium oxide are discussed to obtain understanding of d° ferromagnetism.
Collapse
|
9
|
Qian W, Li M, Chen L, Zhang J, Dong C. Improving thermo-electrochemical cell performance by constructing Ag–MgO–CNTs nanocomposite electrodes. RSC Adv 2015. [DOI: 10.1039/c5ra19182c] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Ag–MgO–CNTs nanocomposites were conveniently prepared using a electrophoretic deposition method, leading to significantly improved thermo-electrochemical cell performances.
Collapse
Affiliation(s)
- Weijin Qian
- Institute of Micro-nano Structure & Optoelectronics
- Wenzhou University
- Wenzhou 325035
- P. R. China
| | - Mengjie Li
- Institute of Micro-nano Structure & Optoelectronics
- Wenzhou University
- Wenzhou 325035
- P. R. China
| | - Lihong Chen
- Institute of Micro-nano Structure & Optoelectronics
- Wenzhou University
- Wenzhou 325035
- P. R. China
| | - Jianghui Zhang
- Institute of Micro-nano Structure & Optoelectronics
- Wenzhou University
- Wenzhou 325035
- P. R. China
| | - Changkun Dong
- Institute of Micro-nano Structure & Optoelectronics
- Wenzhou University
- Wenzhou 325035
- P. R. China
| |
Collapse
|