Article
Engineering, Electrical & Electronic
Y. Zaoui, K. O. Obodo, L. Beldi, B. Bouhafs
Summary: Density functional theory was used to calculate the properties of Fe/MgO/Fe (001) magnetic tunnel junctions, highlighting the significant effects of interfacial oxygen atoms on the structural, magnetic, and electronic behavior of the system. The Fe/MgO/Fe structure exhibited metallic behavior with a Fe-O interface layer, and the polarization was found to be highly sensitive to the nature of the interface layer.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2021)
Article
Nanoscience & Nanotechnology
Hua Bai, Xinyi Li, Hui Pan, Pimo He, Zhu-an Xu, Yunhao Lu
Summary: This study proposes a new type of two-dimensional tunnel junction, named antiferroelectric magnetic tunnel junction (AFMTJ), which inherits features of both MTJs and AFTJs. Quantum-mechanical modeling demonstrates significant tunneling electroresistance effects and multiple nonvolatile resistance states in AFMTJs. The remarkably low RA product of AFMTJs makes them superior to conventional MFTJs in terms of promising nonvolatile memory applications.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Multidisciplinary Sciences
Suyogya Karki, Vivian Rogers, Priyamvada Jadaun, Daniel S. Marshall, Jean Anne C. Incorvia
Summary: The study suggests that scandium nitride could be a potential barrier material for spintronic devices, as it shows high magnetoresistance compared to magnesium oxide.
ADVANCED THEORY AND SIMULATIONS
(2021)
Article
Physics, Applied
Tatsuya Yamamoto, Tomohiro Ichinose, Jun Uzuhashi, Takayuki Nozaki, Tadakatsu Ohkubo, Kay Yakushiji, Shingo Tamaru, Hitoshi Kubota, Akio Fukushima, Kazuhiro Hono, Shinji Yuasa
Summary: In this study, we investigate the perpendicular magnetic anisotropy (PMA) in MgO/CoFeB (CFB)/MgO junctions by introducing an angstrom-thick Mo spacer layer. It is found that perpendicularly magnetized CFB/Mo/CFB films can be obtained for a wide range of CFB thicknesses, achieving a large PMA energy density. The voltage-controlled magnetic anisotropy effect shows a sign inversion between the 'top free' and 'bottom free' magnetic tunnel junctions, indicating the importance of the flatness of the CFB/MgO interface for improving the efficiency of the effect.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Yukie Kitaoka, Hiroshi Imamura
Summary: Recent research has shown that the perpendicular magnetic anisotropy (PMA) of magnetoresistive random access memory (MRAM) can be significantly enhanced by inserting an ultrathin LiF layer at an Fe/MgO interface. First-principles calculations revealed that the PMA enhancement is mainly due to the suppression of Fe and O atom mixing at the interface. Additionally, in-plane Fe-F coupling contributes positively to the magnetocrystalline anisotropy energy (MAE), while Fe-O coupling has a negative contribution. These findings are valuable for the design of high-PMA materials.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Khondker Shihabul Hoque, Ahmed Zubair
Summary: This study investigates the possibility of inducing magnetization in tungsten selenide monolayer by alloying with vanadium selenide. The results show that as the proportion of vanadium atoms in the alloys increases, a phase transition from semiconducting to metallic to semiconducting is discovered, and all alloy compositions demonstrate induced magnetism with a long-range ferromagnetic order.
Article
Chemistry, Multidisciplinary
Alejandro Schulman, Elvira Paz, Tim Bohnert, Alex Steven Jenkins, Ricardo Ferreira
Summary: Magnetic tunnel junctions (MTJs) and memristors are emerging nanotechnologies that have attracted significant attention for their potential applications in sensing, data storage, and computation. This study demonstrates the co-existence of magnetoresistance and memristive properties on MTJs, showing potential for multifunctional devices. Furthermore, doping the oxide barrier lowers the power consumption of the memristive behavior, enhancing the scalability potential. These findings pave the way for integrating memristors and spintronic devices in complex reprogrammable circuits.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Bao-Huei Huang, Chia-Chia Chao, Yu-Hui Tang
Summary: In this study, a divide-and-conquer method was developed under the framework of first-principles calculation to address the computational challenges of solving Hamiltonian of large devices. The implementation revealed the oscillatory decay of layer-resolved spin torques away from the MgO/Fe interface and suggested a very thin Fe layer thickness below 2 nm for efficient current-driven magnetization switch. The newly developed JunPy-DC calculation efficiently resolves the current self-consistent difficulties in noncollinear spin torque effects for novel spintronic applications with complex magnetic heterostructures.
Article
Nanoscience & Nanotechnology
Bin Liu, Sicong Zhu, Tongtong Wang, Sheng Liu
Summary: The development of multi-value logic (MVL) computing nanodevices based on conventional materials faces challenges such as low peak-valley ratio(PVR) and unstable spin filtering effects. This study designs spintronic magnetic tunnel junctions (MTJs) using Sc2CHO as half-metallic electrodes and Sc2NHO as semiconductor-based scattering regions. The transport properties of the MTJs are simulated using density functional theory combined with nonequilibrium Green's function, and the effect of the length of the scattering region is considered. The MTJs demonstrate stable spintronic transport with perfect 100% polarizability spin currents and exhibit a significant negative differential resistance(NDR) phenomenon, with the highest PVR among two-dimensional spintronic nanodevices currently explored.
ACS APPLIED NANO MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
L. Gladczuk, P. Dluzewski, K. Lasek, P. Aleshkevych, D. M. Burn, G. van der Laan, T. Hesjedal
Summary: In this study, layer-resolved ferromagnetic resonance was used to investigate the coupling between the magnetic layers of a Co/MgO/Permalloy magnetic tunnel junction, showing a strong interlayer interaction through the insulating MgO barrier. A theoretical model including exchange coupling and spin pumping was developed and fits to the experimental data were compared using a likelihood ratio test, providing unambiguous proof of the existence of interlayer coupling mediated by spin pumping.
Article
Materials Science, Multidisciplinary
A. Meo, S. Sampan-a-pai, P. B. Visscher, R. Chepulskyy, D. Apalkov, J. Chureemart, P. Chureemart, R. W. Chantrell, R. F. L. Evans
Summary: The study investigates the spin transfer torque switching dynamics in CoFeB/MgO/CoFeB magnetic tunnel junctions using atomistic simulations based on Slonczewski's model. The results demonstrate a magnetization reversal driven by the combination of coherent and nonuniform excitation modes, affected by factors such as current density, temperature, and structural imperfections. This deeper understanding can be valuable for spin transfer torque dynamics in nanoscale devices.
Article
Physics, Applied
Jianhua Ma, Yunkun Xie, Kamaram Munira, Avik W. Ghosh, William H. Butler
Summary: The combination of half-metallic XYZ half-Heusler alloys with MgO to create Heusler-MgO junctions has been found to exhibit specific electronic and magnetic properties. The type of interface layers plays a crucial role in determining the half-metallicity and anisotropy in these structures.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Multidisciplinary Sciences
Maria Almeida, Apoorva Sharma, Patrick Matthes, Nicole Koehler, Sandra Busse, Matthias Mueller, Olav Hellwig, Alexander Horn, Dietrich R. T. Zahn, Georgeta Salvan, Stefan E. Schulz
Summary: This study investigates the method of locally triggered crystallization of 10 nm thick Co-Fe-B films by laser irradiation, which can achieve similar crystallization effects compared to furnace annealing, and laser annealing has the potential to locally enhance the TMR ratio, especially for MgO capping layers with lower laser intensity requirements.
SCIENTIFIC REPORTS
(2021)
Article
Materials Science, Multidisciplinary
Yanjie Wang, Xiaoyuan Nie, Junhui Song, Chao Wang, Fan Yang, Yaodan Chi, Xiaotian Yang, Ye Shen, Chunyan Xu
Summary: Using first-principles calculations, the diffusion process of B atoms and the origin of perpendicular magnetic anisotropy (PMA) in MgO|CoFe|Ta structures with boron were studied. It was observed that B atoms are more likely to enter the Ta layer than the FeCo and MgO layers, which is consistent with experimental and theoretical results. The physical origin of the interfacial PMA in the Ta|CoFe|MgO structure with B element was also elucidated and found to come from both the MgO|CoFe and CoFe|Ta layer interfaces. These findings provide a comprehensive understanding of PMA and suggest the potential for achieving high thermal stability in advanced-node STT-MRAM.
RESULTS IN PHYSICS
(2023)
Article
Chemistry, Physical
Jiagang Chen, Liang Huang, Long Dong, Haijun Zhang, Zhong Huang, Faliang Li, Shaowei Zhang
Summary: In this study, density functional theory calculations and ab initio molecular simulations were used to investigate the hydration behavior of MgO and the effect of the anti-hydration agent citric acid. The results showed that a defective surface with low coordinated Mg atoms is more easily hydrated. Water reacts quickly with unsaturated Mg atoms, and the increasing water content facilitates hydration. Citric acid can coordinate with Mg atoms, reducing reactivity with water and protecting MgO from hydration. These findings provide important insights for understanding the hydration behavior of MgO and developing new anti-hydration agents.
APPLIED SURFACE SCIENCE
(2023)
Review
Nanoscience & Nanotechnology
Yihan Xiao, Yan Wang, Shou-Hang Bo, Jae Chul Kim, Lincoln J. Miara, Gerbrand Ceder
NATURE REVIEWS MATERIALS
(2020)
Article
Chemistry, Physical
Matteo Bianchini, Jingyang Wang, Raphaele J. Clement, Bin Ouyang, Penghao Xiao, Daniil Kitchaev, Tan Shi, Yaqian Zhang, Yan Wang, Haegyeom Kim, Mingjian Zhang, Jianming Bai, Feng Wang, Wenhao Sun, Gerbrand Ceder
Correction
Nanoscience & Nanotechnology
Yihan Xiao, Yan Wang, Shou-Hang Bo, Jae Chul Kim, Lincoln J. Miara, Gerbrand Ceder
Summary: The paper has been updated with an amendment, which can be accessed through a link at the top of the paper.
NATURE REVIEWS MATERIALS
(2021)
Article
Chemistry, Physical
Xinyou Ke, Yan Wang, Liming Dai, Chris Yuan
ENERGY STORAGE MATERIALS
(2020)
Article
Chemistry, Physical
Xuyong Peng, Po-Hsiu Chien, Yan Wang, Sawankumar Patel, Pengbo Wang, Haoyu Liu, Marcello Immediato-Scuotto, Yan-Yan Hu
ENERGY STORAGE MATERIALS
(2020)
Article
Chemistry, Physical
Ryounghee Kim, Lincoln J. Miara, Jung-Hwa Kim, Ju-Sik Kim, Dongmin Im, Yan Wang
Summary: In this study, Si-doped lithium tantalum phosphates were designed and synthesized as solid-state ionic conductors, showing high ionic conductivity. The enhanced lithium diffusion and activation of an isotropic diffusion pathway in the structure, as well as the reduction of grain boundary resistance, contributed to the improved performance of the materials.
CHEMISTRY OF MATERIALS
(2021)
Article
Multidisciplinary Sciences
Bin Ouyang, Jingyang Wang, Tanjin He, Christopher J. Bartel, Haoyan Huo, Yan Wang, Valentina Lacivita, Haegyeom Kim, Gerbrand Ceder
Summary: This paper presents stability rules for NASICON-structured materials, developed through high-throughput computations and validated through synthesis. A machine-learned tolerance factor based on specific descriptors offers reasonable accuracy in predicting the stability of NASICON phases. This work not only provides tools for understanding the synthetic accessibility of NASICON-type materials, but also demonstrates an efficient paradigm for discovering new materials with complicated composition and atomic structure.
NATURE COMMUNICATIONS
(2021)
Article
Chemistry, Physical
KyuJung Jun, Yingzhi Sun, Yihan Xiao, Yan Zeng, Ryounghee Kim, Haegyeom Kim, Lincoln J. Miara, Dongmin Im, Yan Wang, Gerbrand Ceder
Summary: Superionic lithium conductivity has been observed in only a few materials, mainly in thiophosphates and rarely in oxides. This study reveals that the corner-sharing connectivity in the oxide crystal structure framework promotes superionic conductivity. By conducting a high-throughput search, the researchers discovered ten new oxide frameworks predicted to exhibit superionic conductivity. They also experimentally confirmed the high ionic conductivity of LiGa(SeO3)(2), demonstrating its potential as a new oxide electrolyte. These findings offer insight into the factors that govern fast lithium mobility in oxide materials and will accelerate the development of all-solid-state batteries.
Article
Chemistry, Multidisciplinary
Panawan Vanaphuti, Zeyi Yao, Yangtao Liu, Yulin Lin, Jianguo Wen, Zhenzhen Yang, Zimin Feng, Xiaotu Ma, Anna C. Zauha, Yan Wang, Yan Wang
Summary: P2-type sodium-manganese-based layered cathodes show potential for replacing Li-ion batteries in certain applications. A cobalt-free P2-Na0.72Mn0.75Li0.24X0.01O2 (X = Ti/Si) cathode with high sustainability is developed, which exhibits outstanding capacity and voltage retention. The presence of Ti acts as a protective layer to alleviate side reactions, while Si regulates the local electronic structure and suppresses oxygen redox activities. The cathode also shows superior cycle performance and inhibits microcracking and planar gliding within the particles, making it a promising candidate for high-performance low-cost sodium-ion batteries.
Article
Multidisciplinary Sciences
Sewon Kim, Ju-Sik Kim, Lincoln Miara, Yan Wang, Sung-Kyun Jung, Seong Yong Park, Zhen Song, Hyungsub Kim, Michael Badding, JaeMyung Chang, Victor Roev, Gabin Yoon, Ryounghee Kim, Jung-Hwa Kim, Kyungho Yoon, Dongmin Im, Kisuk Kang
Summary: This study reports lithium metal batteries using tailored solid electrolytes, which exhibit remarkable stability and energy density, meeting commercial lifespan requirements. The compatibility between the solid electrolyte LLZO and lithium metal is crucial for long-term stability.
NATURE COMMUNICATIONS
(2022)
Article
Multidisciplinary Sciences
Yan Zeng, Bin Ouyang, Jue Liu, Young-Woon Byeon, Zijian Cai, Lincoln J. Miara, Yan Wang, Gerbrand Ceder
Summary: Experiments demonstrate that using high-entropy metal cation mixes can improve the ionic conductivity of a compound, reduce reliance on specific chemistries, and enhance synthesizability. Local distortions introduced into high-entropy materials create an overlapping distribution of site energies for alkali ions, allowing them to percolate with low activation energy. This study provides important insights into selecting optimal distortion and designing high-entropy superionic conductors across a wide compositional space.
Article
Multidisciplinary Sciences
Jingyang Wang, Tanjin He, Xiaochen Yang, Zijian Cai, Yan Wang, Valentina Lacivita, Haegyeom Kim, Bin Ouyang, Gerbrand Ceder
Summary: In this paper, the authors investigate the influence of chemical composition on the Na-ion conductivity of NASICON materials through first-principles calculations, experimental synthesis and testing, and text-mined historical data. They successfully synthesized and investigated several new NASICON solid-state conductors, achieving a high ionic conductivity of 1.2 mS cm(-1) at 25 degrees C.
NATURE COMMUNICATIONS
(2023)
Article
Chemistry, Physical
Shafee Farzanian, Joseph Vazquez Mercado, Imtiaz Shozib, Nikhil Sivadas, Valentina Lacivita, Yan Wang, Qingsong Howard Tu
Summary: This study focuses on the investigation of mechanical defects in composite cathodes in all-solid-state batteries during electrochemical cycling. The research highlights the dependence of these defects on the properties of solid electrolyte materials, external stack pressure, and cathode active material loading. The results provide guidelines for optimizing the mechanical properties of composite cathodes to improve the performance of all-solid-state batteries.
ACS APPLIED ENERGY MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Dmitry Skachkov, Shuang-Long Liu, Yan Wang, Xiao-Guang Zhang, Hai-Ping Cheng
Summary: The study presents a first-principles theory for Schottky barrier physics, utilizing density functional theory to compute the Schottky barrier including thousands of atomic layers in the semiconductor. Self-consistent solutions of the Poisson equation provide induced charge and electrostatic potential, leading to the determination of Schottky barrier height. Tests on GaAs-graphene and Si/Al heterostructures demonstrate the self-consistent determination of SBH, width, and depletion and inversion layers as functions of temperature and bulk doping.
Review
Chemistry, Physical
Xinyou Ke, Yan Wang, Guofeng Ren, Chris Yuan
ENERGY STORAGE MATERIALS
(2020)
