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Bhattacharya J, Rawat A, Pati R, Chakrabarti A, Pandey R. Spin dependent tunneling and strain sensitivity in a Co 2MnSb/HfIrSb magnetic tunneling junction: a first-principles study. Phys Chem Chem Phys 2024; 26:26064-26075. [PMID: 39377102 DOI: 10.1039/d4cp01850h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/09/2024]
Abstract
Half-metallic Co-based full Heusler alloys have captured considerable attention of researchers in the realm of spintronic applications, owing to their remarkable characteristics such as exceptionally high spin polarization at the Fermi level, ultra-low Gilbert damping, and a high Curie temperature. In this comprehensive study, employing the density functional theory, we delve into the electronic stability and ballistic spin transport properties of a magnetic tunneling junction (MTJ) comprising a Co2MnSb/HfIrSb interface. An in-depth investigation of k-dependent spin transmissions uncovers the occurrence of coherent tunneling for the Mn-Mn/Ir interface, particularly when a spacer layer beyond a certain thickness is employed. It has been found that the Co-terminated Co2MnSb/HfIrSb interface shows perpendicular magnetic anisotropy, while those with Mn-Sb and Mn-Mn termination exhibit in-plane magnetic anisotropy. Furthermore, our spin-dependent transmission calculations demonstrate that the Mn-Mn/Ir interface manifests strain-sensitive transmission properties under both compressive and tensile strain and yields a remarkable three-fold increase in majority spin transmission under tensile strain conditions. We find a tunnel magnetoresistance of ∼500% under a bi-axial strain of -3%, beyond which the tunnel resistance is found to be theoretically infinite. These compelling outcomes place the Co2MnSb/HfIrSb junction among the highly promising candidates for nanoscale spintronic devices, emphasizing the potential significance of the system in the advancement of the field.
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Affiliation(s)
- Joydipto Bhattacharya
- Raja Ramanna Centre for Advanced Technology, Indore 452013, India.
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
| | - Ashima Rawat
- Department of Physics, Michigan Technological University, Houghton, Michigan 49931, USA
| | - Ranjit Pati
- Department of Physics, Michigan Technological University, Houghton, Michigan 49931, USA
| | - Aparna Chakrabarti
- Raja Ramanna Centre for Advanced Technology, Indore 452013, India.
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
| | - Ravindra Pandey
- Department of Physics, Michigan Technological University, Houghton, Michigan 49931, USA
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Li K, Guo Y, Robertson J, Zhao W, Lu H. Designing van der Waals magnetic tunnel junctions with high tunnel magnetoresistance via Brillouin zone filtering. NANOSCALE 2024. [PMID: 39292184 DOI: 10.1039/d4nr02717e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/19/2024]
Abstract
Magnetic tunnel junctions (MTJs) consisting of two-dimensional (2D) van der Waals heterostructures have no inter-layer chemical bonds; therefore, their spin tunneling is determined solely by the Brillouin zone (BZ) filtering effect. To obtain high tunnel magnetoresistance (TMR), they should possess transversal momentum-resolved conduction channels for the electrodes and transmission channels for the barriers. Here, we investigate 2D magnets as electrodes whose Curie temperatures approach room temperature and also hexagonal 2D insulators as the barrier. Iron-based compounds such as FexGeTe2 (x = 3 and 4) are calculated to have high transmission coefficients over the entire in-plane BZ for the majority spin channel, while this should only happen around Γ for the minority spin channel. Correspondingly, various 2H-type transition metal dichalcogenides (TMDs) are found to function effectively as spin barriers, where electrons are only allowed to tunnel through them around the K and M points. BZ spin filtering is confirmed to be the major mechanism of the TMR effect by the MTJ transport calculation using the non-equilibrium Green function method. Furthermore, the TMR is calculated to be nearly independent of the barrier layer thickness as the BZ filtering is an interfacial effect. This work sheds light on material selection procedures and designing ultra-thin and robust van der Waals MTJs.
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Affiliation(s)
- Kun Li
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing, 100191, China.
- National Key Lab of Spintronics, Institute of International Innovation, Beihang University, Yuhang District, Hangzhou, 311115, China
| | - Yuzheng Guo
- School of Electrical Engineering and Automation, Wuhan University, Wuhan 430072, China
| | - John Robertson
- Engineering Department, Cambridge University, Cambridge CB2 1PZ, UK
| | - Weisheng Zhao
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing, 100191, China.
- National Key Lab of Spintronics, Institute of International Innovation, Beihang University, Yuhang District, Hangzhou, 311115, China
| | - Haichang Lu
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing, 100191, China.
- National Key Lab of Spintronics, Institute of International Innovation, Beihang University, Yuhang District, Hangzhou, 311115, China
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Wu R, Zhang H, Ma H, Zhao B, Li W, Chen Y, Liu J, Liang J, Qin Q, Qi W, Chen L, Li J, Li B, Duan X. Synthesis, Modulation, and Application of Two-Dimensional TMD Heterostructures. Chem Rev 2024; 124:10112-10191. [PMID: 39189449 DOI: 10.1021/acs.chemrev.4c00174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/28/2024]
Abstract
Two-dimensional (2D) transition metal dichalcogenide (TMD) heterostructures have attracted a lot of attention due to their rich material diversity and stack geometry, precise controllability of structure and properties, and potential practical applications. These heterostructures not only overcome the inherent limitations of individual materials but also enable the realization of new properties through appropriate combinations, establishing a platform to explore new physical and chemical properties at micro-nano-pico scales. In this review, we systematically summarize the latest research progress in the synthesis, modulation, and application of 2D TMD heterostructures. We first introduce the latest techniques for fabricating 2D TMD heterostructures, examining the rationale, mechanisms, advantages, and disadvantages of each strategy. Furthermore, we emphasize the importance of characteristic modulation in 2D TMD heterostructures and discuss some approaches to achieve novel functionalities. Then, we summarize the representative applications of 2D TMD heterostructures. Finally, we highlight the challenges and future perspectives in the synthesis and device fabrication of 2D TMD heterostructures and provide some feasible solutions.
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Affiliation(s)
- Ruixia Wu
- Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082, China
- Hunan Provincial Key Laboratory of Two-Dimensional Materials, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Hongmei Zhang
- Hunan Provincial Key Laboratory of Two-Dimensional Materials, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Huifang Ma
- Innovation Center for Gallium Oxide Semiconductor (IC-GAO), National and Local Joint Engineering Laboratory for RF Integration and Micro-Assembly Technologies, College of Integrated Circuit Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
- School of Flexible Electronics (Future Technologies) Institute of Advanced Materials, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, Nanjing 211816, China
| | - Bei Zhao
- School of Physics and Key Laboratory of Quantum Materials and Devices of Ministry of Education, Southeast University, Nanjing 211189, China
| | - Wei Li
- Hunan Provincial Key Laboratory of Two-Dimensional Materials, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Yang Chen
- Hunan Provincial Key Laboratory of Two-Dimensional Materials, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Jianteng Liu
- Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Jingyi Liang
- Hunan Provincial Key Laboratory of Two-Dimensional Materials, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Qiuyin Qin
- Hunan Provincial Key Laboratory of Two-Dimensional Materials, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Weixu Qi
- Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Liang Chen
- Hunan Provincial Key Laboratory of Two-Dimensional Materials, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Jia Li
- Hunan Provincial Key Laboratory of Two-Dimensional Materials, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Bo Li
- Changsha Semiconductor Technology and Application Innovation Research Institute, School of Physics and Electronics, College of Semiconductors (College of Integrated Circuits), Hunan University, Changsha 410082, China
| | - Xidong Duan
- Hunan Provincial Key Laboratory of Two-Dimensional Materials, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
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Feng W, Gemming T, Giebeler L, Qu J, Weinel K, Jácome LA, Büchner B, Gonzalez-Martinez I. Influence of magnetic field on electron beam-induced Coulomb explosion of gold microparticles in transmission electron microscopy. Ultramicroscopy 2024; 262:113978. [PMID: 38692141 DOI: 10.1016/j.ultramic.2024.113978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 02/21/2024] [Accepted: 04/20/2024] [Indexed: 05/03/2024]
Abstract
In this work we instigated the fragmentation of Au microparticles supported on a thin amorphous carbon film by irradiating them with a gradually convergent electron beam inside the Transmission Electron Microscope. This phenomenon has been generically labeled as "electron beam-induced fragmentation" or EBIF and its physical origin remains contested. On the one hand, EBIF has been primarily characterized as a consequence of beam-induced heating. On the other, EBIF has been attributed to beam-induced charging eventually leading to Coulomb explosion. To test the feasibility of the charging framework for EBIF, we instigated the fragmentation of Au particles under two different experimental conditions. First, with the magnetic objective lens of the microscope operating at full capacity, i.e. background magnetic field B=2 T, and with the magnetic objective lens switched off (Lorenz mode), i.e. B=0 T. We observe that the presence or absence of the magnetic field noticeably affects the critical current density at which EBIF occurs. This strongly suggests that magnetic field effects play a crucial role in instigating EBIF on the microparticles. The dependence of the value of the critical current density on the absence or presence of an ambient magnetic field cannot be accounted for by the beam-induced heating model. Consequently, this work presents robust experimental evidence suggesting that Coulomb explosion driven by electrostatic charging is the root cause of EBIF.
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Affiliation(s)
- Wen Feng
- Leibniz Institute for Solid State and Materials Research (IFW) Dresden, Helmholtzstr.20, Dresden, 01069, Germany.
| | - Thomas Gemming
- Leibniz Institute for Solid State and Materials Research (IFW) Dresden, Helmholtzstr.20, Dresden, 01069, Germany
| | - Lars Giebeler
- Leibniz Institute for Solid State and Materials Research (IFW) Dresden, Helmholtzstr.20, Dresden, 01069, Germany
| | - Jiang Qu
- Leibniz Institute for Solid State and Materials Research (IFW) Dresden, Helmholtzstr.20, Dresden, 01069, Germany
| | - Kristina Weinel
- Federal Institute for Materials Research and Testing (BAM), Unter den Eichen 87, Berlin, 12205, Germany
| | - Leonardo Agudo Jácome
- Federal Institute for Materials Research and Testing (BAM), Unter den Eichen 87, Berlin, 12205, Germany
| | - Bernd Büchner
- Leibniz Institute for Solid State and Materials Research (IFW) Dresden, Helmholtzstr.20, Dresden, 01069, Germany
| | - Ignacio Gonzalez-Martinez
- Leibniz Institute for Solid State and Materials Research (IFW) Dresden, Helmholtzstr.20, Dresden, 01069, Germany.
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Harfah H, Wicaksono Y, Sunnardianto GK, Majidi MA, Kusakabe K. Ultra-thin van der Waals magnetic tunnel junction based on monoatomic boron vacancy of hexagonal boron nitride. Phys Chem Chem Phys 2024; 26:9733-9740. [PMID: 38470432 DOI: 10.1039/d4cp00218k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/13/2024]
Abstract
We present a novel strategy to create a van der Waals-based magnetic tunnel junction (MTJ) comprising a three-atom layer of graphene (Gr) sandwiched with hexagonal boron nitride (hBN) layers by introducing a monoatomic boron vacancy in each hBN layer. The magnetic properties and electronic structure of the system were investigated using density functional theory (DFT) and the transmission probability of the MTJ was investigated using the Landauer-Büttiker formalism within the non-equilibrium Green function method. The Stoner gap was created between the spin-majority channel and the spin-minority channel on the local density of states of the hBN monoatomic boron-vacancy (VB) near the Fermi energy, creating a possible control of the spin valve by considering two magnetic alignment of hBN(VB) layers, anti-parallel configuration (APC) and parallel configuration (PC). The transmission probability calculation results showed a high electron transmission in the PC of the hBN(VB) layers and a low transmission when the APC was considered. A high tunneling magnetoresistance (TMR) ratio of approximately 400% was observed when comparing the APC and PC of the hBN(VB) layers in hBN(VB)/Gr/hBN(VB), giving the highest TMR ratio for the thinnest MTJ system.
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Affiliation(s)
- Halimah Harfah
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-Cho, Toyonaka, Osaka 560-0043, Japan.
| | - Yusuf Wicaksono
- RIKEN Cluster for Pioneering Research (CPR), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Gagus Ketut Sunnardianto
- Research Center for Quantum Physics, National Research and Innovation Agency (BRIN), Tangerang Selatan, Banten, 15314, Indonesia
- Research Collaboration Center for Quantum Technology 2.0, Bandung 40132, Indonesia
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Muhammad Aziz Majidi
- Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Indonesia, Kampus UI Depok, Depok 16424, Indonesia
| | - Koichi Kusakabe
- School of Science, Graduate School of Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, 678-1297, Hyogo, Japan
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6
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Chen X, Zhang X, Xiang G. Recent advances in two-dimensional intrinsic ferromagnetic materials Fe 3X( X=Ge and Ga)Te 2 and their heterostructures for spintronics. NANOSCALE 2024; 16:527-554. [PMID: 38063022 DOI: 10.1039/d3nr04977a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Owing to their atomic thicknesses, atomically flat surfaces, long-range spin textures and captivating physical properties, two-dimensional (2D) magnetic materials, along with their van der Waals heterostructures (vdWHs), have attracted much interest for the development of next-generation spin-based materials and devices. As an emergent family of intrinsic ferromagnetic materials, Fe3X(X=Ge and Ga)Te2 has become a rising star in the fields of condensed matter physics and materials science owing to their high Curie temperature and large perpendicular magnetic anisotropy. Herein, we aim to comprehensively summarize the recent progress on 2D Fe3X(X=Ge and Ga)Te2 and their vdWHs and provide a panorama of their physical properties and underlying mechanisms. First, an overview of Fe3X(X=Ge and Ga)Te2 is presented in terms of crystalline and electronic structures, distinctive physical properties and preparation methods. Subsequently, the engineering of electronic and spintronic properties of Fe3X(X=Ge and Ga)Te2 by diverse means, including strain, gate voltage, substrate and patterning, is surveyed. Then, the latest advances in spintronic devices based on 2D Fe3X(X=Ge and Ga)Te2 vdWHs are discussed and elucidated in detail, including vdWH devices that exploit the exchange bias effect, magnetoresistance effect, spin-orbit torque effect, magnetic proximity effect and Dzyaloshinskii-Moriya interaction. Finally, the future outlook is given in terms of efficient large-scale fabrication, intriguing physics and important technological applications of 2D Fe3X(X=Ge and Ga)Te2 and their vdWHs. Overall, this study provides an overview to support further studies of emergent 2D Fe3X(X=Ge and Ga)Te2 materials and related vdWH devices for basic science and practical applications.
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Affiliation(s)
- Xia Chen
- College of Physics, Sichuan University, Chengdu 610064, China.
| | - Xi Zhang
- College of Physics, Sichuan University, Chengdu 610064, China.
| | - Gang Xiang
- College of Physics, Sichuan University, Chengdu 610064, China.
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7
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Man P, Huang L, Zhao J, Ly TH. Ferroic Phases in Two-Dimensional Materials. Chem Rev 2023; 123:10990-11046. [PMID: 37672768 DOI: 10.1021/acs.chemrev.3c00170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/08/2023]
Abstract
Two-dimensional (2D) ferroics, namely ferroelectric, ferromagnetic, and ferroelastic materials, are attracting rising interest due to their fascinating physical properties and promising functional applications. A variety of 2D ferroic phases, as well as 2D multiferroics and the novel 2D ferrovalleytronics/ferrotoroidics, have been recently predicted by theory, even down to the single atomic layers. Meanwhile, some of them have already been experimentally verified. In addition to the intrinsic 2D ferroics, appropriate stacking, doping, and defects can also artificially regulate the ferroic phases of 2D materials. Correspondingly, ferroic ordering in 2D materials exhibits enormous potential for future high density memory devices, energy conversion devices, and sensing devices, among other applications. In this paper, the recent research progresses on 2D ferroic phases are comprehensively reviewed, with emphasis on chemistry and structural origin of the ferroic properties. In addition, the promising applications of the 2D ferroics for information storage, optoelectronics, and sensing are also briefly discussed. Finally, we envisioned a few possible pathways for the future 2D ferroics research and development. This comprehensive overview on the 2D ferroic phases can provide an atlas for this field and facilitate further exploration of the intriguing new materials and physical phenomena, which will generate tremendous impact on future functional materials and devices.
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Affiliation(s)
- Ping Man
- Department of Chemistry and Center of Super-Diamond & Advanced Films (COSDAF), City University of Hong Kong, Kowloon, Hong Kong 999077, P. R. China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, P. R. China
| | - Lingli Huang
- Department of Chemistry and Center of Super-Diamond & Advanced Films (COSDAF), City University of Hong Kong, Kowloon, Hong Kong 999077, P. R. China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, P. R. China
| | - Jiong Zhao
- Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong 999077, P. R. China
- The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen 518057, P. R. China
| | - Thuc Hue Ly
- Department of Chemistry and Center of Super-Diamond & Advanced Films (COSDAF), City University of Hong Kong, Kowloon, Hong Kong 999077, P. R. China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, P. R. China
- Department of Chemistry and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon, Hong Kong 999077, P. R. China
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Chen Z, Liu X, Li X, Gao P, Li Z, Zhu W, Wang H, Li X. Large tunneling magnetoresistance in spin-filtering 1T-MnSe 2/h-BN van der Waals magnetic tunnel junction. NANOSCALE 2023; 15:8447-8455. [PMID: 37097089 DOI: 10.1039/d3nr00045a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The magnetic tunnel junction (MTJ), one of the most prominent spintronic devices, has been widely utilized for memory and computation systems. Electrical writing is considered as a practical method to enhance the performance of MTJs with high circuit integration density and ultralow-power consumption. Meanwhile, a large tunneling magnetoresistance (TMR), especially at the non-equilibrium state, is desirable for the improvement of the sensitivity and stability of MTJ devices. However, achieving both aspects efficiently is still challenging. Here, we propose a two-dimensional (2D) MTJ of 1T-MnSe2/h-BN/1T-MnSe2/h-BN/1T-MnSe2 with efficient electrical writing, reliable reading operations and high potential to work at room temperature. First, for this proposed MTJ with a symmetrical structure and an antiparallel magnetic state, the degeneracy of the energy could be broken by an electric field, resulting in a 180° magnetization reversal. A first principles study confirms that the magnetization of the center 1T-MnSe2 layer could be reversed by changing the direction of the electric field, when the magnetic configurations of the two outer 1T-MnSe2 layers are fixed in the antiparallel state. Furthermore, we report a theoretical spin-related transport investigation of the MTJ at the non-equilibrium state. Thanks to the half-metallicity of 1T-MnSe2, TMR ratios reach very satisfactory values of 2.56 × 103% with the magnetization information written by an electric field at room temperature. In addition, the performance of the TMR effect exhibits good stability even when the bias voltage increases gradually. Our theoretical findings show that this proposed MTJ is a promising high performance spintronic device and could promote the design of ultralow-power spintronic devices.
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Affiliation(s)
- Zhao Chen
- Department of Physics, Hefei University of Technology, Hefei, Anhui 230009, China.
| | - Xiaofeng Liu
- Department of Physics, Hefei University of Technology, Hefei, Anhui 230009, China.
| | - Xingxing Li
- Department of Chemical Physics, Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China.
| | - Pengfei Gao
- Interdisciplinary Center for Fundamental and Frontier Sciences, Nanjing University of Science and Technology, Jiangyin, Jiangsu, 214443, China
| | - ZhongJun Li
- Department of Physics, Hefei University of Technology, Hefei, Anhui 230009, China.
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Shanxi University, Taiyuan 030006, China
| | - Weiduo Zhu
- Department of Physics, Hefei University of Technology, Hefei, Anhui 230009, China.
| | - Haidi Wang
- Department of Physics, Hefei University of Technology, Hefei, Anhui 230009, China.
| | - Xiangyang Li
- School of Materials Science and Engineering, Anhui University, Hefei, Anhui 230601, China
- Department of Chemical Physics, Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China.
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Larionov KV, Pais Pereda JJ, Li S, Sakai S, Sorokin PB. Half-Metallic Heusler Alloy/MoS 2 Based Magnetic Tunnel Junction. ACS APPLIED MATERIALS & INTERFACES 2022; 14:55167-55173. [PMID: 36459613 DOI: 10.1021/acsami.2c09655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Integration of half-metallic materials and 2D spacers into vertical magnetoresistive spin valves may pave the way for effective low-power consumption storage and memory technologies. Driven by the recent successful growth of graphene/half-metallic Co2Fe(Ge1/2Ga1/2) (CFGG) heterostructure, here we report a theoretical investigation of magnetic tunnel junction (MTJ) based on the ferromagnetic CFGG Heusler alloy and the MoS2 spacer of different thicknesses. Using ab initio approach, we demonstrate that the inherent ferromagnetism of CFGG is preserved at the interface, while its half-metallicity is recovering within few atomic layers. Ballistic transport in CFGG/MoS2/CFGG MTJ is studied within the nonequilibrium Green's function formalism, and a large magnetoresistance value up to ∼105% is observed. These findings support the idea of effective spintronics devices based on half-metallic Heusler alloys and highly diversified transition metal dichalcogenide family.
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Affiliation(s)
- Konstantin V Larionov
- National University of Science and Technology MISiS, 4 Leninskiy Prospect, Moscow119049, Russian Federation
| | - Jose J Pais Pereda
- National University of Science and Technology MISiS, 4 Leninskiy Prospect, Moscow119049, Russian Federation
| | - Songtian Li
- Quantum Beam Science Research Directorate, National Institutes for Quantum Science and Technology, 1233 Watanuki, Takasaki370-1292, Japan
| | - Seiji Sakai
- Quantum Beam Science Research Directorate, National Institutes for Quantum Science and Technology, 1233 Watanuki, Takasaki370-1292, Japan
| | - Pavel B Sorokin
- National University of Science and Technology MISiS, 4 Leninskiy Prospect, Moscow119049, Russian Federation
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Zhang Y, Liu J, Deng R, Shi X, Tang H, Chen H, Yuan H. Electronic structure, magnetoresistance and spin filtering in graphene|2 monolayer-CrI3 3|graphene van der Waals magnetic tunnel junctions. RSC Adv 2022; 12:28533-28544. [PMID: 36320544 PMCID: PMC9536253 DOI: 10.1039/d2ra02988j] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 09/20/2022] [Indexed: 11/28/2022] Open
Abstract
In the pursuit of designing van der Waals magnetic tunneling junctions (vdW-MTJs) with two-dimensional (2D) intrinsic magnets, as well as to quantitatively reveal the microscopic nature governing the vertical tunneling pathways beyond the phenomenological descriptions on CrI3-based vdW-MTJs, we investigate the structural configuration, electronic structure and spin-polarized quantum transport of graphene|2 monolayer(2ML)-CrI3|graphene heterostructure with Ag(111) layers as the electrode, using density functional theory (DFT) and its combination of non-equilibrium Green's function (DFT-NEGF) methods. The in-plane lattice of CrI3 layers is found to be stretched when placed on the graphene (Gr) layer, and the layer-stacking does not show any site selectivity. The charge transfer between CrI3 and Gr layers make the CrI3 layer lightly electron-doped, and the Gr layer hole-doped. Excitingly, the inter-layer hybridization between graphene and CrI3 layers render the CrI3 layer metallic in the majority spin channel, giving rise to an insulator-to-half-metal transition. Due to the metallic/insulator characteristics of the spin-majority/minority channel of the 2ML-CrI3 barrier in vdW-MTJs, Gr|2ML-CrI3|Gr heterostructures exhibit an almost perfect spin filtering effect (SFE) near the zero bias in parallel magnetization, a giant tunneling magnetoresistance (TMR) ratio up to 2 × 104%, and remarkable negative differential resistance (NDR). Our results not only give an explanation for the observed giant TMR in CrI3-based MTJs but also show the direct implications of 2D magnets in vdW-heterostructures.
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Affiliation(s)
- Yibin Zhang
- School of Physical Science and Technology, Southwest University Chongqing 400715 China
| | - Jie Liu
- School of Physical Science and Technology, Southwest University Chongqing 400715 China
| | - Renhao Deng
- School of Physical Science and Technology, Southwest University Chongqing 400715 China
| | - Xuan Shi
- Center of Quantum Information Technology, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences Chongqing 400714 China
- College of Artificial Intelligence, Chongqing School, University of Chinese Academy of Sciences Chongqing 400714 China
| | - Huan Tang
- School of Physical Science and Technology, Southwest University Chongqing 400715 China
| | - Hong Chen
- School of Physical Science and Technology, Southwest University Chongqing 400715 China
| | - Hongkuan Yuan
- School of Physical Science and Technology, Southwest University Chongqing 400715 China
- Chongqing Key Laboratory of Micro&Nano Structure Optoelectronics Chongqing 400715 China
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Das S, Kabiraj A, Mahapatra S. Room temperature giant magnetoresistance in half-metallic Cr 2C based two-dimensional tunnel junctions. NANOSCALE 2022; 14:9409-9418. [PMID: 35730762 DOI: 10.1039/d2nr02056d] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Two-dimensional (2D) magnetic materials inherit enormous potential to revolutionize next-generation spintronic technology. The majority of prior investigations using 2D ferromagnet-based tunnel junctions have shown encouraging tunnel magnetoresistance (TMR) at low temperatures. Using first-principles-based calculations, here we investigate the magnetic properties of commercially available Cr2C crystals at their monolayer limit and reveal their half metallicity properties far beyond room temperature. We then design hetero-multilayer structures combining Cr2C with graphene and hexagonal boron nitride (h-BN) and report their magnetoresistance using spin-polarized quantum transport calculations. While graphene based devices, adsorbed on the metal contact, reveal a very high TMR (1200%), it can be further increased to 1500% by changing the barrier layer to h-BN. The dependence of TMR on the number of barrier layers and different metallic electrode materials (Ti, Ag, and Au) are also studied. Our investigation suggests that Cr2C based spin valves can serve as the perfect building blocks for room temperature all-2D spintronic devices.
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Affiliation(s)
- Shreeja Das
- Nano-Scale Device Research Laboratory, Department of Electronic Systems Engineering, Indian Institute of Science (IISc), Bangalore, Bangalore 560012, India.
| | - Arnab Kabiraj
- Nano-Scale Device Research Laboratory, Department of Electronic Systems Engineering, Indian Institute of Science (IISc), Bangalore, Bangalore 560012, India.
| | - Santanu Mahapatra
- Nano-Scale Device Research Laboratory, Department of Electronic Systems Engineering, Indian Institute of Science (IISc), Bangalore, Bangalore 560012, India.
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12
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Chen Y, Tang Z, Dai M, Luo X, Zheng Y. Giant magnetoresistance and tunneling electroresistance in multiferroic tunnel junctions with 2D ferroelectrics. NANOSCALE 2022; 14:8849-8857. [PMID: 35695845 DOI: 10.1039/d2nr00785a] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Multiferroic tunneling junctions (MFTJs), composed of two magnetic electrodes separated by an ultrathin ferroelectric (FE) thin film as a barrier, have received great attention in multi-functional devices. Recent theoretical and experimental works have revealed that ferroelectric polarization exists at room temperature in two-dimensional ferroelectric (2D FE) materials within the ultrathin thickness. Here we propose a novel MFTJ Ni/bilayer In2Se3/BN/Ni, in which the resistance of the tunneling spin polarization electrons can be modulated by different magnetization alignments of the electrode and electric polarization direction of the 2D FE In2Se3 layer, leading to multiple tunneling resistance states. The tunneling magnetoresistance (TMR) and electroresistance (TER) of MFTJs are enhanced by the inserted h-BN layer, achieving an ON/OFF TER ratio of 4188% as well as a TMR ratio of 581% with a much lower resistance area. The giant tunneling resistance ratio, multiple resistance states, and ultra-low energy consumption in 2D FE-based MFTJs suggest their great potential in non-destructive non-volatile memories.
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Affiliation(s)
- Yancong Chen
- Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices, School of Physics, Sun Yat-sen University, Guangzhou 510275, China.
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, Guangzhou 510275, China
- Centre for Physical Mechanics and Biophysics, School of Physics, Sun Yat-sen University, Guangzhou 510275, China
| | - Zhiyuan Tang
- Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices, School of Physics, Sun Yat-sen University, Guangzhou 510275, China.
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, Guangzhou 510275, China
- Centre for Physical Mechanics and Biophysics, School of Physics, Sun Yat-sen University, Guangzhou 510275, China
| | - Minzhi Dai
- Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices, School of Physics, Sun Yat-sen University, Guangzhou 510275, China.
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, Guangzhou 510275, China
- Centre for Physical Mechanics and Biophysics, School of Physics, Sun Yat-sen University, Guangzhou 510275, China
| | - Xin Luo
- Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices, School of Physics, Sun Yat-sen University, Guangzhou 510275, China.
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, Guangzhou 510275, China
- Centre for Physical Mechanics and Biophysics, School of Physics, Sun Yat-sen University, Guangzhou 510275, China
| | - Yue Zheng
- Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices, School of Physics, Sun Yat-sen University, Guangzhou 510275, China.
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, Guangzhou 510275, China
- Centre for Physical Mechanics and Biophysics, School of Physics, Sun Yat-sen University, Guangzhou 510275, China
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Yu H, Li D, Shang Y, Pei L, Zhang G, Yan H, Wang L. Transport properties of MoS 2/V 7(Bz) 8 and graphene/V 7(Bz) 8 vdW junctions tuned by bias and gate voltages. RSC Adv 2022; 12:17422-17433. [PMID: 35765433 PMCID: PMC9189623 DOI: 10.1039/d2ra02196j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 06/06/2022] [Indexed: 12/02/2022] Open
Abstract
The MoS2/V7(Bz)8 and graphene/V7(Bz)8 vdW junctions are designed and the transport properties of their four-terminal devices are comparatively investigated based on density functional theory (DFT) and the nonequilibrium Green's function (NEGF) technique. The MoS2 and graphene nanoribbons act as the source-to-drain channel and the spin-polarized one-dimensional (1D) benzene-V multidecker complex nanowire (V7(Bz)8) serves as the gate channel. Gate voltages applied on V7(Bz)8 exert different influences of electron transport on MoS2/V7(Bz)8 and graphene/V7(Bz)8. In MoS2/V7(Bz)8, the interplay of source and gate bias potentials could induce promising properties such as negative differential resistance (NDR) behavior, output/input current switching, and spin-polarized currents. In contrast, the gate bias plays an insignificant effect on the transport along graphene in graphene/V7(Bz)8. This dissimilarity is attributed to the fact that the conductivity follows the sequence of MoS2 < V7(Bz)8 < graphene. These transport characteristics are examined by analyzing the conductivity, the currents, the local density of states (LDOS), and the transmission spectra. These results are valuable in designing multi-terminal nanoelectronic devices.
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Affiliation(s)
- Hong Yu
- School of Materials Science and Chemical Engineering, Harbin University of Science and Technology Harbin 150040 P. R. China
| | - Danting Li
- School of Materials Science and Chemical Engineering, Harbin University of Science and Technology Harbin 150040 P. R. China
| | - Yan Shang
- School of Materials Science and Chemical Engineering, Harbin University of Science and Technology Harbin 150040 P. R. China
| | - Lei Pei
- School of Materials Science and Chemical Engineering, Harbin University of Science and Technology Harbin 150040 P. R. China
| | - Guiling Zhang
- School of Materials Science and Chemical Engineering, Harbin University of Science and Technology Harbin 150040 P. R. China
| | - Hong Yan
- School of Materials Science and Chemical Engineering, Harbin University of Science and Technology Harbin 150040 P. R. China
| | - Long Wang
- HeiLongJiang Construction Investment Group Co. Ltd No. 523, Sanda Dongli Road Harbin 150040 P. R. China
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14
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Zhang Y, Cui Z, Sa B, Miao N, Zhou J, Sun Z. Computational design of double transition metal MXenes with intrinsic magnetic properties. NANOSCALE HORIZONS 2022; 7:276-287. [PMID: 35108718 DOI: 10.1039/d1nh00621e] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Two-dimensional transition metal carbides (MXenes) have great potential to achieve intrinsic magnetism due to their available chemical and structural diversity. In this work, by spin-polarized density functional theory calculations, we designed and comprehensively investigated 50 double transition metal (DTM) MXenes MCr2CTx (T = H, O, F, OH, or bare) based on the chemical formula of M2C (M = Sc, Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W). We highlight that ferromagnetic half-metallicity, antiferromagnetic semiconduction, as well as antiferromagnetic half-metallicity have been achieved in the DTM MXenes. Herein, ferromagnetic half-metallic ScCr2C2, ScCr2C2H2, ScCr2C2F2, and YCr2C2H2 are characterized with wide band gaps and high Curie temperatures. Very interestingly, the ScCr2C2-based magnetic tunnel junction presents a tunnel magnetoresistance ratio as high as 176 000%. In addition, the antiferromagnetic semiconducting TiCr2C2, ZrCr2C2, and ZrCr2C2(OH)2, possessing moderate band gaps and high Néel temperatures, have been predicted. Especially, the Néel temperature of ZrCr2C2(OH)2 can reach 425 K. Moreover, the Dirac cone-like band structure feature is highlighted in antiferromagnetic half-metallic ZrCr2C2H2. Our study provides a new potential strategy for designing MXenes in spintronics.
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Affiliation(s)
- Yinggan Zhang
- College of Materials, Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, Xiamen University, Xiamen 361005, P. R. China
| | - Zhou Cui
- Key Laboratory of Eco-materials Advanced Technology, College of Materials Science and Engineering, Fuzhou University, Fuzhou 350108, P. R. China.
| | - Baisheng Sa
- Key Laboratory of Eco-materials Advanced Technology, College of Materials Science and Engineering, Fuzhou University, Fuzhou 350108, P. R. China.
| | - Naihua Miao
- School of Materials Science and Engineering and Center for Integrated Computational Materials Science, International Research Institute for Multidisciplinary Science, Beihang University, Beijing 100191, P. R. China.
| | - Jian Zhou
- School of Materials Science and Engineering and Center for Integrated Computational Materials Science, International Research Institute for Multidisciplinary Science, Beihang University, Beijing 100191, P. R. China.
| | - Zhimei Sun
- School of Materials Science and Engineering and Center for Integrated Computational Materials Science, International Research Institute for Multidisciplinary Science, Beihang University, Beijing 100191, P. R. China.
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15
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Yu S, Tang J, Wang Y, Xu F, Li X, Wang X. Recent advances in two-dimensional ferromagnetism: strain-, doping-, structural- and electric field-engineering toward spintronic applications. SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 2022; 23:140-160. [PMID: 35185390 PMCID: PMC8856075 DOI: 10.1080/14686996.2022.2030652] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 01/03/2022] [Accepted: 01/09/2022] [Indexed: 05/27/2023]
Abstract
Since the first report on truly two-dimensional (2D) magnetic materials in 2017, a wide variety of merging 2D magnetic materials with unusual physical characteristics have been discovered and thus provide an effective platform for exploring the associated novel 2D spintronic devices, which have been made significant progress in both theoretical and experimental studies. Herein, we make a comprehensive review on the recent scientific endeavors and advances on the various engineering strategies on 2D ferromagnets, such as strain-, doping-, structural- and electric field-engineering, toward practical spintronic applications, including spin tunneling junctions, spin field-effect transistors and spin logic gate, etc. In the last, we discuss on current challenges and future opportunities in this field, which may provide useful guidelines for scientists who are exploring the fundamental physical properties and practical spintronic devices of low-dimensional magnets.
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Affiliation(s)
- Sheng Yu
- Institute of Information Technology, Shenzhen Institute of Information Technology, Shenzhen, China
- Institute for Advanced Study, Shenzhen University, Shenzhen, China
| | - Junyu Tang
- Department of Physics and Astronomy, University of California, Riverside, CA, USA
| | - Yu Wang
- Institute for Advanced Study, Shenzhen University, Shenzhen, China
| | - Feixiang Xu
- Institute for Advanced Study, Shenzhen University, Shenzhen, China
| | - Xiaoguang Li
- Institute for Advanced Study, Shenzhen University, Shenzhen, China
| | - Xinzhong Wang
- Institute of Information Technology, Shenzhen Institute of Information Technology, Shenzhen, China
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16
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Yu H, Shao Z, Tao Y, Jiang X, Dong Y, Zhang J, Liu Y, Yang X, Chen D. Tunable tunneling magnetoresistance in in-plane double barrier magnetic tunnel junctions based on B vacancy h-NB nanoribbons. Phys Chem Chem Phys 2022; 24:3451-3459. [PMID: 35076037 DOI: 10.1039/d1cp04895c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Magnetic tunnel junctions (MTJs) have attained new opportunities due to the emergence of two-dimensional (2D) magnetic materials after they were proposed more than forty years ago. Here, an in-plane double barrier magnetic tunnel junction (IDB-MTJ) based on B vacancy h-NB nanoribbons has been proposed firstly, and the transport properties have been studied using density functional theory combined with the nonequilibrium Green's function method. Due to its unique structural characteristics, the tunneling magnetoresistance (TMR) ratio can be tuned and the maximum TMR can reach 1.86 × 105. The potential applications of the IDB-MTJ in magnetic random-access memories and logical computation have also been discussed. We find that the IDB-MTJs have great potential in magnetic random-access memories and logical computation applications.
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Affiliation(s)
- Hailin Yu
- School of Electronic and Information Engineering, Changshu Institute of Technology, Changshu, 215500, China. .,The Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China.
| | - Zhenguang Shao
- School of Electronic and Information Engineering, Changshu Institute of Technology, Changshu, 215500, China.
| | - Yongmei Tao
- School of Electronic and Information Engineering, Changshu Institute of Technology, Changshu, 215500, China.
| | - Xuefan Jiang
- School of Electronic and Information Engineering, Changshu Institute of Technology, Changshu, 215500, China.
| | - Yaojun Dong
- School of Electronic and Information Engineering, Changshu Institute of Technology, Changshu, 215500, China.
| | - Jie Zhang
- School of Electronic and Information Engineering, Changshu Institute of Technology, Changshu, 215500, China.
| | - Yushen Liu
- School of Electronic and Information Engineering, Changshu Institute of Technology, Changshu, 215500, China.
| | - Xifeng Yang
- School of Electronic and Information Engineering, Changshu Institute of Technology, Changshu, 215500, China.
| | - Dunjun Chen
- The Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China.
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17
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Liu J, Tang H, Gan M, Chen H, Shi X, Yuan H. Above-room Curie temperature and barrier-layer-dependent tunneling magnetoresistance in 1T-CrO2 monolayer based magnetic tunnel junction. Phys Chem Chem Phys 2022; 24:22007-22015. [DOI: 10.1039/d2cp01924h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Van der Waals (vdW) heterostructures based on two-dimensional (2D) ferromagnetic materials hold great potential applications in spintronics. Owing to high Curie temperature (TC) of 392 K as well as moderate...
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18
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Li D, Li S, Zhong C, He J. Tuning magnetism at the two-dimensional limit: a theoretical perspective. NANOSCALE 2021; 13:19812-19827. [PMID: 34825688 DOI: 10.1039/d1nr06835k] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The discovery of two-dimensional (2D) magnetic materials provides an ideal testbed for manipulating the magnetic properties at the atomically thin and 2D limit. This review gives recent progress in the emergent 2D magnets and heterostructures, focusing on the theory side. We summarize different theoretical models, ranging from the atomic to micrometer-scale, used to describe magnetic orders. Then, the current strategies for tuning magnetism in 2D materials are further discussed, such as electric field, magnetic field, strain, optics, chemical functionalization, and spin-orbit engineering. Finally, we conclude with the future challenges and opportunities for 2D magnetism.
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Affiliation(s)
- Dongzhe Li
- Institute for Advanced Study, Chengdu University, Chengdu 610100, P. R. China.
| | - Shuo Li
- Institute for Advanced Study, Chengdu University, Chengdu 610100, P. R. China.
| | - Chengyong Zhong
- Institute for Advanced Study, Chengdu University, Chengdu 610100, P. R. China.
| | - Junjie He
- Bremen Center for Computational Materials Science, University of Bremen, Am Fallturm 1, 2835, Bremen, Germany
- Department of Physical and Macromolecular Chemistry & Charles University Centre of Advanced Materials, Faculty of Science, Charles University in Prague, Hlavova 8, Prague 2, 128 43, Czech Republic.
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19
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Lu H, Guo Y, Robertson J. Ab Initio Study of Hexagonal Boron Nitride as the Tunnel Barrier in Magnetic Tunnel Junctions. ACS APPLIED MATERIALS & INTERFACES 2021; 13:47226-47235. [PMID: 34559966 DOI: 10.1021/acsami.1c13583] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Two-dimensional hexagonal boron nitride (h-BN) is studied as a tunnel barrier in magnetic tunnel junctions (MTJs) as a possible alternative to MgO. The tunnel magnetoresistance (TMR) of such MTJs is calculated as a function of whether the interface involves the chemi- or physisorptive site of h-BN atoms on the metal electrodes, Fe, Co, or Ni. It is found that the physisorptive site on average produces higher TMR values, whereas the chemisorptive site has the greater binding energy but lower TMR. It is found that alloying the electrodes with an inert metal-like Pt can induce the preferred absorption site on Co to become a physisorptive site, enabling a higher TMR value. It is found that the choice of physisorptive sites of each element gives more Schottky-like dependence of their Schottky barrier heights on the metal work function.
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Affiliation(s)
- Haichang Lu
- School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, China
- Engineering Department, Cambridge University, Cambridge CB2 1PZ, U.K
| | - Yuzheng Guo
- Engineering Department, Cambridge University, Cambridge CB2 1PZ, U.K
- School of Engineering, Swansea University, Swansea SA1 8EN, U.K
| | - John Robertson
- Engineering Department, Cambridge University, Cambridge CB2 1PZ, U.K
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