Article
Materials Science, Ceramics
Zhen Teng, Yongqiang Tan, Sifan Zeng, Yan Meng, Chen Chen, Xiaochun Han, Haibin Zhang
Summary: This study successfully synthesized 37 kinds of high-entropy pyrochlore/fluorite ceramics, with 33 of them showing a single-phase structure where all cations are randomly distributed. Ionic radii, valence, and size disorder play a key role in the formation of single-phase high-entropy pyrochlore/fluorite oxides. The average radius ratio(rA/rB) is the main factor influencing the phase transformation of pyrochlore/fluorite.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2021)
Article
Materials Science, Ceramics
Florianne Vayer, Claudia Decorse, David Berardan, Diana Dragoe, Nita Dragoe
Summary: This article reports the exploration of the chemical versatility of entropy-stabilized pyrochlores (A(2)B(2)O(7)) with large chemical disorder introduced on the B site. It also investigates the effects of isovalent and aliovalent substitution on the B site and Ca2+-doping on the A site. The study obtained 20 new compounds, including 8 entropy-stabilized ones, and screened their physical properties for potential applications.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2023)
Article
Materials Science, Ceramics
Zili Liu, Chong Wei, Songbin Zhang, Cheng Zhang, Xiaoqiang Li
Summary: High-entropy pyrochlore ceramics have been prepared by synthesizing a range of medium and high-entropy Ti-based pyrochlore powders using a two-step method. The crystal structure was adjusted to avoid the formation of a monoclinic phase, and high-density pyrochlore ceramic bulks with a uniform distribution of elements were prepared.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2023)
Article
Chemistry, Inorganic & Nuclear
Uyen Dang, Jake O'Hara, Hayden A. . Evans, Daniel Olds, Juan Chamorro, Daniel Hickox-Young, Geneva Laurita, Robin T. Macaluso
Summary: This study focuses on the control of ordered lone pair behavior in lead-based materials. Through the investigation of Pb1.53Nb2O6.5, it is found that local distortions are present at all temperatures and can be described by the ordered arrangement of cations. The crystallographic site disorder of vacancies inhibits long range correlation of lone pair-driven distortions, preventing a low-temperature phase transition and resulting in an elevated dielectric permittivity across a broad temperature range.
INORGANIC CHEMISTRY
(2022)
Article
Materials Science, Ceramics
Liang Xu, Min Niu, Hongjie Wang, Lei Su, Hongfei Gao, Lei Zhuang
Summary: This paper presents the synthesis of high-entropy (La0.2Ce0.2Nd0.2Sm0.2Gd0.2)(2)Zr2O7 with a pyrochlore-type structure through a conventional solid-state method. The material exhibits superior damage tolerance and resistance to heavy-ion irradiation, making it a promising candidate for immobilization of high-level radioactive waste and advanced nuclear reactor systems. The study also discusses the mechanisms behind its resistance to irradiation and observes improved mechanical properties.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2022)
Article
Physics, Multidisciplinary
Hui Li, Shuailing Ma, Jili Ye, Xin Wang
Summary: The pyrochlore manganate In2Mn2O7 is a very promising ferromagnetic semiconductor material with low electron effective mass, high Curie temperature, and structural stability. Experimental results showed that the structure of In2Mn2O7 is very stable under high pressure, making it suitable for extreme environments.
FRONTIERS IN PHYSICS
(2021)
Article
Materials Science, Ceramics
Patrick Hutterer, Maren Lepple
Summary: Rare-earth zirconates with high-entropy were successfully synthesized using reverse coprecipitation. By systematically varying the composition of the cations, the phase and chemical composition, as well as the morphology of the materials were investigated. The phase stability and structure of the synthesized zirconates were also studied.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2023)
Review
Chemistry, Multidisciplinary
Pralay Gayen, Sulay Saha, Vijay Ramani
Summary: This article discusses the importance of low-cost electrocatalysts in fuel cells, water electrolyzers, unitized regenerative fuel cells, and metal-air batteries by studying the structure-activity relationship of pyrochlore oxides. Pyrochlore oxides have the ability to tune their structure and electronic properties, resulting in excellent bifunctional oxygen electrocatalytic activity and high OER selectivity for a wide range of applications. The article also discusses the recent developments and applications of pyrochlore-based electrocatalysts.
ACCOUNTS OF CHEMICAL RESEARCH
(2022)
Article
Chemistry, Multidisciplinary
Chenhui Zhou, Xiao Chen, Shuo Liu, Ying Han, Haibing Meng, Qinyuan Jiang, Siming Zhao, Fei Wei, Jie Sun, Ting Tan, Rufan Zhang
Summary: A Mn-doped RuO2 bimetallic oxide with atomic-scale dispersion of Mn atoms exhibits remarkable activity and super durability for both ORR and OER, providing a new catalyst design strategy for Zn-air batteries.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Materials Science, Multidisciplinary
M. V. Talanov, A. A. Pavelko, L. S. Kamzina
Summary: Cadmium niobate Cd2Nb2O7 is a rare example of a bulk ferroelectric with a pyrochlore structure, exhibiting complex phase diagram and contradictions in structural phase transitions and polar states. Studies show that its dielectric behavior demonstrates typical features of domain-wall freezing dynamics, expanding the limited family of ferroelectrics exhibiting this phenomenon.
MATERIALS RESEARCH BULLETIN
(2022)
Article
Chemistry, Physical
Lin Zhu, Chenglong Ma, Zhiqiang Wang, Xueqing Gong, Limei Cao, Ji Yang
Summary: The intrinsic activity of M2Ir2O7 iridium-based pyrochlores is effectively promoted by partial substitution of Zn2+ for Lu3+ or Pr3+, resulting in high mass activity for the Pr1.8Zn0.2Ir2O7 and Lu1.8Zn0.2Ir2O7 electrocatalysts. This work demonstrates that doping of Zn2+ reduces defective oxygen and regulates electron distribution, leading to an upshift of the O-2p band center which promotes Ir-O covalency and accelerates the OER process.
APPLIED SURFACE SCIENCE
(2022)
Article
Chemistry, Physical
Florianne Vayer, Claudia Decorse, David Berardan, Nita Dragoe
Summary: This article presents a new entropy-stabilized oxide with unique structure and physical properties suitable for potential applications as thermal barrier coatings.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Chemistry, Multidisciplinary
Jian Sun, Jing Zhou, Lili Li, Zhiwei Hu, Ting-Shan Chan, Tonya Vitova, Sanzhao Song, Renduo Liu, Chao Jing, Haisheng Yu, Ming Zhang, Joerg Rothe, Jian-Qiang Wang, Linjuan Zhang
Summary: For the first time, 100% substitution of Zr4+ by U6+ in a La2Zr2O7 matrix has been achieved using the molten salt method. The uranium was found to be precisely anchored into the Zr or La sites of the matrix. This work provides guidance for the development of site-controlled and high-capacity actinide-immobilized materials.
CHEMICAL COMMUNICATIONS
(2022)
Article
Multidisciplinary Sciences
Hui Liu, Xiaoming Shi, Yonghao Yao, Huajie Luo, Qiang Li, Houbing Huang, He Qi, Yuanpeng Zhang, Yang Ren, Shelly D. Kelly, Krystian Roleder, Joerg C. Neuefeind, Long-Qing Chen, Xianran Xing, Jun Chen
Summary: This study used the advanced big-box refinement method to extract local atomic polar displacements and construct 3D polar configurations in the classical relaxor ferroelectric Pb(Mg1/3Nb2/3)O-3-PbTiO3. The results showed that the prevailing order-disorder character and continuous rotation of local polar displacements drive the composition-driven global structure evolution. The competition between different states of local polar order-disorder contributes to the high piezoelectricity, clarifying the critical structural feature required for high piezoelectricity.
NATURE COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Jiandi Li, Aijun Gong, Xingyan Li, Yanfei He, Jinsheng Li, Yuzhen Bai, Rongrong Fan
Summary: In this work, a cubic Ce2-xTi2O7 pyrochlore was prepared using the sol-gel method, and its crystal structure, thermostability, and magnetism were studied. It was found that the as-prepared samples had 18(1)% vacancy of Ce ions and exhibited magnetism at high temperatures.
Article
Materials Science, Ceramics
Jianxiong Lan, Pengfei Zhai, Shuai Nan, Lijun Xu, Jingjing Niu, Cheng Tian, Zongzhen Li, Weixing Li, Jie Liu, Rodney Charles Ewing
Summary: This study investigates the high-pressure phase stability of CeO2 irradiated by swift heavy ions using high-pressure Raman spectroscopy. The results show that high-fluence ion irradiation significantly enhances the phase stability of CeO2, attributed to the formation of large interstitial-type defect clusters.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2022)
Article
International Relations
Sulgiye Park, Allison Puccioni, Rodney C. Ewing
Summary: This case study demonstrates that automated image analysis using Earth observation satellites can effectively track nuclear activities and international trade, improving the efficiency and quality of data collection.
BULLETIN OF THE ATOMIC SCIENTISTS
(2022)
Article
Engineering, Environmental
Kazuki Fueda, Ryu Takami, Kenta Minomo, Kazuya Morooka, Kenji Horie, Mami Takehara, Shinya Yamasaki, Takumi Saito, Hiroyuki Shiotsu, Toshihiko Ohnuki, Gareth T. W. Law, Bernd Grambow, Rodney C. Ewing, Satoshi Utsunomiya
Summary: Boron carbide control rods in the damaged reactors of Fukushima Daiichi Nuclear Power Plant may prevent re-criticality, but their state and stability are unknown. Analyses of radioactive Cs-rich microparticles show B-Li isotopic signatures, indicating reactions occurred in B4C before the meltdowns. The released amount of B is enough to prevent re-criticality, but its heterogeneous distribution should be considered during decommissioning.
JOURNAL OF HAZARDOUS MATERIALS
(2022)
Article
Geology
Sulgiye Park, Terence P. McNulty, Rodney C. Ewing
Summary: This article provides a comprehensive analysis of critical metals resources in DPRK, revealing that previous estimates of its resource base were exaggerated. While there is a possibility of discovering new ore deposits, DPRK needs to develop a nationwide strategy to attract foreign investments for accessing its resources.
INTERNATIONAL GEOLOGY REVIEW
(2023)
Article
Chemistry, Physical
Md Ehsan Sadat, Sergey L. Bud'ko, Rodney C. Ewing, Hong Xu, Giovanni M. Pauletti, David B. Mast, Donglu Shi
Summary: The effects of dipole interactions on the magnetization and relaxation dynamics of magnetic nanoparticles were studied using five different nanoparticle systems. It was found that dipole interactions play a crucial role in modifying the blocking temperature behavior of superparamagnetic nanoparticles. The frequencies of the dominant relaxation mechanisms were determined, and microwave absorption was found to depend on the local environment and dipole-dipole interactions.
Article
Nanoscience & Nanotechnology
Yuxin Li, Yiming Lei, Shuang Zhao, Hao Xiao, Haocheng Liu, Yugang Wang, Yixiu Luo, Jie Zhang, Jingyang Wang, Rodney C. Ewing, Chenxu Wang
Summary: Two high entropy pyrochlores (HEPs), Gd2(Ti0.2Zr0.2Sn0.2Hf0.2Ta0.2)2O7 and Gd2(Ti0.2Zr0.2Sn0.2Hf0.2Nb0.2)2O7, were irradiated with 800 keV Kr2+ ions and observed by in situ transmission electron microscopy (TEM). The order-to-disorder phase transformation from pyrochlore to fluorite structure was observed in these HEPs and Gd2Sn2O7 through selected area electron diffraction (SAED), high angle annular dark field scanning transmission electron microscopy (HAADF-STEM), and energy dispersive spectroscopy (EDS) mapping. Density functional theory (DFT) calculations were used to determine the cation antisite defect (CAD) formation energy and the electron localization function (ELF). Both experimental and calculated results indicate that HEPs have higher resistance to phase transformation and amorphization compared to Gd2Sn2O7.
SCRIPTA MATERIALIA
(2023)
Letter
International Relations
Cameron L. Tracy, David Wright
Summary: A recent study by Candler and Leyva in Science & Global Security critiques our 2020 paper on modeling hypersonic boost-glide missiles, providing new data on glide vehicle aerodynamics and infrared emissions during the glide phase. Their findings show lower infrared emissions compared to ours but still detectable by modern U.S. space sensors. We discuss incorporating their data into our model and highlight unresolved discrepancies with a previous computational fluid dynamics analysis. Additionally, we acknowledge the role of social processes in shaping knowledge about hypersonic weapon performance.
SCIENCE & GLOBAL SECURITY
(2023)
Article
Geochemistry & Geophysics
Weixing Li, Yahui Shen, Yueqing Zhou, Pengfei Zhai, Shuai Nan, Jie Liu, Rodney C. Ewing
Summary: Fission events in minerals produce damage tracks that contain critical information about events occurring over different time scales. However, the exact location of fission occurrence along these tracks has never been identified. This study utilizes a novel technique to observe unexpectedly narrow fission tracks near the fission event site, contrary to the conventionally assumed largest diameter. These narrow tracks provide vital spatial information for understanding atomic-scale processes, such as track formation and annealing, with significant implications for fission track thermochronology.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Tobias Beirau, Ruediger Kilian, Michael Stipp, Rodney C. Ewing
Summary: Electron backscatter diffraction (EBSD) was used to investigate the structural order of a zoned radiation-damaged zircon on a sub-micron scale. The amorphous fraction of the growth-zones ranged from 45% to 80% due to variations in uranium and thorium content (-0.22- 0.43 wt% UO2 and-0.02-0.08 wt% ThO2) and alpha-decay events over time. The correlation between the Kikuchi pattern parameters and the elastic modulus evolution demonstrated the reliability of the method.
JOURNAL OF NUCLEAR MATERIALS
(2023)
Article
Environmental Studies
Sulgiye Park, Cameron L. Tracy, Rodney C. Ewing
Summary: China has dominated the global production of rare-earth elements (REE) since the 1990s, primarily due to domestic factors. The decline in US REE production, which facilitated China's market dominance, can be attributed to a misalignment between the US government and corporate interests. Strategic cooperation between China and the US in the REE sector could diversify and improve the resilience of supply chains, mitigating potential economic and national security risks.
Article
Chemistry, Physical
Igor M. M. Gussev, Eric C. C. O'Quinn, Matthew Tucker, Rodney C. C. Ewing, Cale Overstreet, Jorg Neuefeind, Michelle Everett, Qiang Zhang, David Sprouster, Daniel Olds, Gianguido Baldinozzi, Maik Lang
Summary: The atomic structures of the lanthanide tantalates, Ln(3)TaO(7), series (Ln = Pr, Tb, Dy, Ho, Tm, Yb) were studied using total scattering techniques. Three distinct families of long-range structures were identified: ordered Cmcm (Ln = Pr), ordered Ccmm (Ln = Tb, Dy, Ho), and disordered, defect-fluorite Fm3m (Ln = Ho, Tm, Yb). Short-range analysis revealed structural heterogeneity and non-centrosymmetric models better captured the coordination polyhedra. These findings contribute to a better understanding of the multiferroic character and structural differences in weberite-type tantalates.
JOURNAL OF MATERIALS CHEMISTRY A
(2023)
Article
International Relations
Cameron L. L. Tracy, Rodney C. C. Ewing
Summary: Efforts to decrease the weapons plutonium stockpiles of the US and Russia have stopped as the US decided to bury excess plutonium in a geologic repository. Russia criticizes this approach, while analysts argue that buried plutonium can be recovered through advanced mining techniques. The controversy arises from different understandings of the permanence and risks of burying plutonium among the two countries.
SCIENCE & GLOBAL SECURITY
(2022)
Article
Environmental Sciences
Haruko Murakami Wainwright, Brian A. Powell, Megan Elisabeth Hoover, Ali Ayoub, Milos Atz, Craig Benson, R. A. Borrelli, Denia Djokic, Carol Ann Eddy-Dilek, Dinara Ermakova, Robert Hayes, Kathryn Higley, Steven Krahn, Leonel Lagos, Sheldon Landsberger, Christina Leggett, Monica Regalbuto, William Roy, Lindsay Shuller-Nickles, Rodney C. Ewing
Summary: A workshop was held at MIT to develop a blueprint for educating future engineers and scientists about nuclear waste management. The workshop identified key needs for teaching students with diverse backgrounds and attracting young people to this field.
JOURNAL OF ENVIRONMENTAL RADIOACTIVITY
(2023)
Article
Materials Science, Multidisciplinary
Wagner M. Nakasuga, Weixing Li, Chien-Hung Chen, Trevor A. Dumitru, Vladimir A. Skuratov, Rodney C. Ewing
Summary: Fission tracks are used for age-dating and thermal history reconstruction. This study compared the thermal-annealing behavior of latent and etched tracks in epidote, finding similar behavior and providing insights into the annealing of latent and etched tracks.
PHYSICS AND CHEMISTRY OF MINERALS
(2022)
