1
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Choi S, Son J, MacManus-Driscoll JL, Lee S. Hydrogen-Driven Low-Temperature Topotactic Transition in Nanocomb Cobaltite for Ultralow Power Ionic-Magnetic Coupled Applications. NANO LETTERS 2024; 24:3606-3613. [PMID: 38483316 DOI: 10.1021/acs.nanolett.3c04414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/28/2024]
Abstract
We reversibly control ferromagnetic-antiferromagnetic ordering in an insulating ground state by annealing tensile-strained LaCoO3 films in hydrogen. This ionic-magnetic coupling occurs due to the hydrogen-driven topotactic transition between perovskite LaCoO3 and brownmillerite La2Co2O5 at a lower temperature (125-200 °C) and within a shorter time (3-10 min) than the oxygen-driven effect (500 °C, tens of hours). The X-ray and optical spectroscopic analyses reveal that the transition results from hydrogen-driven filling of correlated electrons in the Co 3d-orbitals, which successively releases oxygen by destabilizing the CoO6 octahedra into CoO4 tetrahedra. The transition is accelerated by surface exchange, diffusion of hydrogen in and oxygen out through atomically ordered oxygen vacancy "nanocomb" stripes in the tensile-strained LaCoO3 films. Our ionic-magnetic coupling with fast operation, good reproducibility, and long-term stability is a proof-of-principle demonstration of high-performance ultralow power magnetic switching devices for sensors, energy, and artificial intelligence applications, which are keys for attaining carbon neutrality.
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Affiliation(s)
- Songhee Choi
- Department of Physics and Chemistry, DGIST, Daegu 42988, Republic of Korea
| | - Jaeseok Son
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul 08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University, Seoul 08826, Republic of Korea
| | - Judith L MacManus-Driscoll
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, United Kingdom
| | - Shinbuhm Lee
- Department of Physics and Chemistry, DGIST, Daegu 42988, Republic of Korea
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2
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Wang G, Sun F, Zhou S, Zhang Y, Zhang F, Wang H, Huang J, Zheng Y. Enhanced Memristive Performance via a Vertically Heterointerface in Nanocomposite Thin Films for Artificial Synapses. ACS APPLIED MATERIALS & INTERFACES 2024; 16:12073-12084. [PMID: 38381527 DOI: 10.1021/acsami.3c18146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
Memristors can be used to mimic synaptic behavior in artificial neural networks, which makes them a key component in neuromorphic computing and holds promise for advancing the field. In this study, a memory artificial synaptic device based on ZnO-BaTiO3 (ZnO-BTO) vertically aligned nanocomposite thin films was prepared. The vertical interface between the two phases can be used as a conduit for oxygen vacancy (OV) accumulation and a channel for OV movement, which greatly optimizes the resistive switching performance of the device and has the potential for multistage storage. By applying different pulse sequences to the device, the conductance of the device is adjusted from multiple angles, and a variety of synaptic functions are simulated, such as paired-pulse facilitation, spike-timing-dependent plasticity, short-term plasticity to long-term plasticity (STP-LTP), and long-term potentiation/depression (LTP/LTD). Finally, we construct a neural network for image recognition, and the recognition accuracy can reach 91%. Our study demonstrates the feasibility of using composite thin-film vertical interface to regulate the resistive performance of memristors and its great potential in artificial synaptic simulation and neuromorphic computing.
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Affiliation(s)
- Guoliang Wang
- School of Materials, Shenzhen Campus of Sun Yat-sen University, Shenzhen 518107, China
- State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou 510275, China
- Centre for Physical Mechanics and Biophysics, School of Physics, Sun Yat-sen University, Guangzhou 510275, China
| | - Fei Sun
- School of Physics, Sun Yat-sen University, Guangzhou 510275, China
- State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou 510275, China
- Centre for Physical Mechanics and Biophysics, School of Physics, Sun Yat-sen University, Guangzhou 510275, China
| | - Shiyu Zhou
- School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Yizhi Zhang
- School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Fan Zhang
- School of Physics, Sun Yat-sen University, Guangzhou 510275, China
- State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou 510275, China
- Centre for Physical Mechanics and Biophysics, School of Physics, Sun Yat-sen University, Guangzhou 510275, China
| | - Haiyan Wang
- School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Jijie Huang
- School of Materials, Shenzhen Campus of Sun Yat-sen University, Shenzhen 518107, China
- State Key Laboratory of Optoelectronic Materials and Technologies, 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
- School of Physics, Sun Yat-sen University, Guangzhou 510275, China
- State Key Laboratory of Optoelectronic Materials and Technologies, 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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3
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Guo Z, Liu G, Sun Y, Zhang Y, Zhao J, Liu P, Wang H, Zhou Z, Zhao Z, Jia X, Sun J, Shao Y, Han X, Zhang Z, Yan X. High-Performance Neuromorphic Computing and Logic Operation Based on a Self-Assembled Vertically Aligned Nanocomposite SrTiO 3:MgO Film Memristor. ACS NANO 2023; 17:21518-21530. [PMID: 37897737 DOI: 10.1021/acsnano.3c06510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/30/2023]
Abstract
Neuromorphic computing based on memristors capable of in-memory computing is promising to break the energy and efficiency bottleneck of well-known von Neumann architectures. However, unstable and nonlinear conductance updates compromise the recognition accuracy and block the integration of neural network hardware. To this end, we present a highly stable memristor with self-assembled vertically aligned nanocomposite (VAN) SrTiO3:MgO films that achieve excellent resistive switching with low set/reset voltage variability (4.7%/-5.6%) and highly linear conductivity variation (nonlinearity = 0.34) by spatially limiting the conductive channels at the vertical interfaces. Various synaptic behaviors are simulated by continuously modulating the conductance. Especially, convolutional image processing using diverse crossbar kernels is demonstrated, and the artificial neural network achieves an overwhelming recognition accuracy of up to 97.50% for handwritten digits. Even under the perturbation of Poisson noise (λ = 10), 6% Salt and Pepper noise, and 5% Gaussian noise, the high recognition accuracies are retained at 95.43%, 94.56%, and 95.97%, respectively. Importantly, the logic memory function is proven experimentally based on the nonvolatile properties. This work provides a material system and design idea to achieve high-performance neuromorphic computing and logic operation.
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Affiliation(s)
- Zhenqiang Guo
- Institute of Life Science and Green Development, Key Laboratory of Brain-like Neuromorphic Devices and Systems of Hebei Province, College of Electronic and Information Engineering, Hebei University, Baoding 071002, P. R. China
| | - Gongjie Liu
- Institute of Life Science and Green Development, Key Laboratory of Brain-like Neuromorphic Devices and Systems of Hebei Province, College of Electronic and Information Engineering, Hebei University, Baoding 071002, P. R. China
| | - Yong Sun
- Institute of Life Science and Green Development, Key Laboratory of Brain-like Neuromorphic Devices and Systems of Hebei Province, College of Electronic and Information Engineering, Hebei University, Baoding 071002, P. R. China
| | - Yinxing Zhang
- Institute of Life Science and Green Development, Key Laboratory of Brain-like Neuromorphic Devices and Systems of Hebei Province, College of Electronic and Information Engineering, Hebei University, Baoding 071002, P. R. China
| | - Jianhui Zhao
- Institute of Life Science and Green Development, Key Laboratory of Brain-like Neuromorphic Devices and Systems of Hebei Province, College of Electronic and Information Engineering, Hebei University, Baoding 071002, P. R. China
| | - Pan Liu
- Institute of Life Science and Green Development, Key Laboratory of Brain-like Neuromorphic Devices and Systems of Hebei Province, College of Electronic and Information Engineering, Hebei University, Baoding 071002, P. R. China
| | - Hong Wang
- Institute of Life Science and Green Development, Key Laboratory of Brain-like Neuromorphic Devices and Systems of Hebei Province, College of Electronic and Information Engineering, Hebei University, Baoding 071002, P. R. China
| | - Zhenyu Zhou
- Institute of Life Science and Green Development, Key Laboratory of Brain-like Neuromorphic Devices and Systems of Hebei Province, College of Electronic and Information Engineering, Hebei University, Baoding 071002, P. R. China
| | - Zhen Zhao
- Institute of Life Science and Green Development, Key Laboratory of Brain-like Neuromorphic Devices and Systems of Hebei Province, College of Electronic and Information Engineering, Hebei University, Baoding 071002, P. R. China
| | - Xiaotong Jia
- Institute of Life Science and Green Development, Key Laboratory of Brain-like Neuromorphic Devices and Systems of Hebei Province, College of Electronic and Information Engineering, Hebei University, Baoding 071002, P. R. China
| | - Jiameng Sun
- Institute of Life Science and Green Development, Key Laboratory of Brain-like Neuromorphic Devices and Systems of Hebei Province, College of Electronic and Information Engineering, Hebei University, Baoding 071002, P. R. China
| | - Yiduo Shao
- Institute of Life Science and Green Development, Key Laboratory of Brain-like Neuromorphic Devices and Systems of Hebei Province, College of Electronic and Information Engineering, Hebei University, Baoding 071002, P. R. China
| | - Xu Han
- Institute of Life Science and Green Development, Key Laboratory of Brain-like Neuromorphic Devices and Systems of Hebei Province, College of Electronic and Information Engineering, Hebei University, Baoding 071002, P. R. China
| | - Zixuan Zhang
- Institute of Life Science and Green Development, Key Laboratory of Brain-like Neuromorphic Devices and Systems of Hebei Province, College of Electronic and Information Engineering, Hebei University, Baoding 071002, P. R. China
| | - Xiaobing Yan
- Institute of Life Science and Green Development, Key Laboratory of Brain-like Neuromorphic Devices and Systems of Hebei Province, College of Electronic and Information Engineering, Hebei University, Baoding 071002, P. R. China
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4
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Dou H, Lin Z, Hu Z, Tsai BK, Zheng D, Song J, Lu J, Zhang X, Jia Q, MacManus-Driscoll JL, Ye PD, Wang H. Self-Assembled Au Nanoelectrodes: Enabling Low-Threshold-Voltage HfO 2-Based Artificial Neurons. NANO LETTERS 2023; 23:9711-9718. [PMID: 37875263 PMCID: PMC10636789 DOI: 10.1021/acs.nanolett.3c02217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 09/20/2023] [Indexed: 10/26/2023]
Abstract
Filamentary-type resistive switching devices, such as conductive bridge random-access memory and valence change memory, have diverse applications in memory and neuromorphic computing. However, the randomness in filament formation poses challenges to device reliability and uniformity. To overcome this issue, various defect engineering methods have been explored, including doping, metal nanoparticle embedding, and extended defect utilization. In this study, we present a simple and effective approach using self-assembled uniform Au nanoelectrodes to controll filament formation in HfO2 resistive switching devices. By concentrating the electric field near the Au nanoelectrodes within the BaTiO3 matrix, we significantly enhanced the device stability and reduced the threshold voltage by up to 45% in HfO2-based artificial neurons compared to the control devices. The threshold voltage reduction is attributed to the uniformly distributed Au nanoelectrodes in the insulating matrix, as confirmed by COMSOL simulation. Our findings highlight the potential of nanostructure design for precise control of filamentary-type resistive switching devices.
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Affiliation(s)
- Hongyi Dou
- School
of Materials Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Zehao Lin
- Elmore
School of Electrical Engineering, Purdue
University, West Lafayette, Indiana 47907, United States
| | - Zedong Hu
- Elmore
School of Electrical Engineering, Purdue
University, West Lafayette, Indiana 47907, United States
| | - Benson Kunhung Tsai
- School
of Materials Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Dongqi Zheng
- Elmore
School of Electrical Engineering, Purdue
University, West Lafayette, Indiana 47907, United States
| | - Jiawei Song
- School
of Materials Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Juanjuan Lu
- School
of Materials Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Xinghang Zhang
- School
of Materials Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Quanxi Jia
- Department
of Materials Design and Innovation, School of Engineering and Applied
Sciences, University at Buffalo, The State
University of New York, Buffalo, New York 14260, United States
| | | | - Peide D. Ye
- Elmore
School of Electrical Engineering, Purdue
University, West Lafayette, Indiana 47907, United States
| | - Haiyan Wang
- School
of Materials Engineering, Purdue University, West Lafayette, Indiana 47907, United States
- Elmore
School of Electrical Engineering, Purdue
University, West Lafayette, Indiana 47907, United States
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5
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MacManus-Driscoll JL, Wu R, Li W. Interface-related phenomena in epitaxial complex oxide ferroics across different thin film platforms: opportunities and challenges. MATERIALS HORIZONS 2023; 10:1060-1086. [PMID: 36815609 PMCID: PMC10068909 DOI: 10.1039/d2mh01527g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 02/16/2023] [Indexed: 06/18/2023]
Abstract
Interfaces in complex oxides give rise to fascinating new physical phenomena arising from the interconnected spin, lattice, charge and orbital degrees of freedom. Most commonly, interfaces are engineered in epitaxial superlattice films. Of growing interest also are epitaxial vertically aligned nanocomposite films where interfaces form by self-assembly. These two thin film forms offer different capabilities for materials tuning and have been explored largely separately from one another. Ferroics (ferroelectric, ferromagnetic, multiferroic) are among the most fascinating phenomena to be manipulated using interface effects. Hence, in this review we compare and contrast the ferroic properties that arise in these two different film forms, highlighting exemplary materials combinations which demonstrate novel, enhanced and/or emergent ferroic functionalities. We discuss the origins of the observed functionalities and propose where knowledge can be translated from one materials form to another, to potentially produce new functionalities. Finally, for the two different film forms we present a perspective on underexplored/emerging research directions.
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Affiliation(s)
| | - Rui Wu
- Department of Materials Science and Metallurgy, University of Cambridge, Cambridge, CB3 0FS, UK.
- Spin-X Institute, School of Physics and Optoelectronics, State Key Laboratory of Luminescent Materials and Devices, Guangdong-Hong Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional Materials, South China University of Technology, Guangzhou 511442, China
| | - Weiwei Li
- Department of Materials Science and Metallurgy, University of Cambridge, Cambridge, CB3 0FS, UK.
- MIIT Key Laboratory of Aerospace Information Materials and Physics, State Key Laboratory of Mechanics and Control of Mechanical Structures, College of Physics, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, China
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6
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Xue Q, Peng Y, Cao L, Xia Y, Liang J, Chen CC, Li M, Hang T. Ultralow Set Voltage and Enhanced Switching Reliability for Resistive Random-Access Memory Enabled by an Electrodeposited Nanocone Array. ACS APPLIED MATERIALS & INTERFACES 2022; 14:25710-25721. [PMID: 35604125 DOI: 10.1021/acsami.2c03978] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Resistive random-access memory (RRAM) has been extensively investigated for 20 years due to its excellent advantages, including scalability, switching speed, compatibility with the complementary metal oxide semiconductor process, and neuromorphic computing application. However, the issue of memristor reliability for cycle to cycle and device to device resulting from the random ion drift and diffusion in solid-state thin films is still a great challenge for commercialization. Therefore, controlling the internal ionic process to improve the memristor performance and reliability is a primary and urgent task. Here, a Ni nanocone array prepared by an electrodeposition method is integrated with an Ag/Al2O3/Pt resistive switching device. The nanocone-array-based memristor yields superior switching performance, including an ultralow set voltage (-0.37 V), a concentrated voltage/resistance distribution (CV 14.8%/32.7%), robust endurance (>105 cycles), and multilevel storage capability. A finite element analysis, transmission electron microscope observation, and current mapping test indicate that the local enhancement of the electric field confines the ionic migration process and yields a predictable formation and dissolution process of the conductive filament. The nanocone-array-based RRAM device provides a new and feasible method to control the conductive filament growth reliably, which paves the way for memristor development.
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Affiliation(s)
- Qi Xue
- State Key Laboratory of Metal Matrix Composites, School of Material Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
| | - Yan Peng
- State Key Laboratory of Metal Matrix Composites, School of Material Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
| | - Liang Cao
- State Key Laboratory of Metal Matrix Composites, School of Material Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
| | - Yuanyuan Xia
- State Key Laboratory of Metal Matrix Composites, School of Material Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
| | - Jianghu Liang
- State Key Laboratory of Metal Matrix Composites, School of Material Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
| | - Chun-Chao Chen
- State Key Laboratory of Metal Matrix Composites, School of Material Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
| | - Ming Li
- State Key Laboratory of Metal Matrix Composites, School of Material Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
| | - Tao Hang
- State Key Laboratory of Metal Matrix Composites, School of Material Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
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7
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Emergent multiferroism with magnetodielectric coupling in EuTiO3 created by a negative pressure control of strong spin-phonon coupling. Nat Commun 2022; 13:2364. [PMID: 35501352 PMCID: PMC9061821 DOI: 10.1038/s41467-022-30074-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 04/15/2022] [Indexed: 11/24/2022] Open
Abstract
Negative pressure has emerged as a powerful tool to tailor the physical properties of functional materials. However, a negative pressure control of spin-phonon coupling for engineering magnetism and multiferroicity has not been explored to date. Here, using uniform three-dimensional strain-induced negative pressure in nanocomposite films of (EuTiO3)0.5:(MgO)0.5, we demonstrate an emergent multiferroicity with magnetodielectric coupling in EuTiO3, matching exactly with density functional theory calculations. Density functional theory calculations are further used to explore the underlying physics of antiferromagnetic-paraelectric to ferromagnetic-ferroelectric phase transitions, the spin-phonon coupling, and its correlation with negative pressures. The observation of magnetodielectric coupling in the EuTiO3 reveals that an enhanced spin-phonon coupling originates from a negative pressure induced by uniform three-dimensional strain. Our work provides a route to creating multiferroicity and magnetoelectric coupling in single-phase oxides using a negative pressure approach. Negative pressure tailors the physical properties of functional oxide materials. Here, the authors demonstrate an emergent multiferroism with magnetodielectric coupling in EuTiO3 created by a negative pressure control of strong spin-phonon coupling.
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8
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Strain Engineering: A Pathway for Tunable Functionalities of Perovskite Metal Oxide Films. NANOMATERIALS 2022; 12:nano12050835. [PMID: 35269323 PMCID: PMC8912649 DOI: 10.3390/nano12050835] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 02/14/2022] [Accepted: 02/24/2022] [Indexed: 11/16/2022]
Abstract
Perovskite offers a framework that boasts various functionalities and physical properties of interest such as ferroelectricity, magnetic orderings, multiferroicity, superconductivity, semiconductor, and optoelectronic properties owing to their rich compositional diversity. These properties are also uniquely tied to their crystal distortion which is directly affected by lattice strain. Therefore, many important properties of perovskite can be further tuned through strain engineering which can be accomplished by chemical doping or simply element substitution, interface engineering in epitaxial thin films, and special architectures such as nanocomposites. In this review, we focus on and highlight the structure–property relationships of perovskite metal oxide films and elucidate the principles to manipulate the functionalities through different modalities of strain engineering approaches.
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Wang J, Ma L, Wang X, Wang X, Yao J, Yi Q, Tang R, Zou G. Sub‐Nanometer Thick Wafer‐Size NiO Films with Room‐Temperature Ferromagnetic Behavior. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202110185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Jiong Wang
- College of Energy Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province & Key Lab of Modern Optical Technologies of Education Ministry of China Soochow University Suzhou 215123 China
| | - Liang Ma
- College of Energy Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province & Key Lab of Modern Optical Technologies of Education Ministry of China Soochow University Suzhou 215123 China
| | - Xiangyi Wang
- College of Energy Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province & Key Lab of Modern Optical Technologies of Education Ministry of China Soochow University Suzhou 215123 China
| | - Xiaohan Wang
- College of Energy Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province & Key Lab of Modern Optical Technologies of Education Ministry of China Soochow University Suzhou 215123 China
| | - Junjie Yao
- College of Energy Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province & Key Lab of Modern Optical Technologies of Education Ministry of China Soochow University Suzhou 215123 China
| | - Qinghua Yi
- College of Energy Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province & Key Lab of Modern Optical Technologies of Education Ministry of China Soochow University Suzhou 215123 China
| | - Rujun Tang
- School of Physical Science and Technology Jiangsu Key Laboratory of Thin Films Soochow University Suzhou 215123 China
| | - Guifu Zou
- College of Energy Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province & Key Lab of Modern Optical Technologies of Education Ministry of China Soochow University Suzhou 215123 China
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10
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Wang J, Ma L, Wang X, Wang X, Yao J, Yi Q, Tang R, Zou G. Sub-Nanometer Thick Wafer-Size NiO Films with Room-Temperature Ferromagnetic Behavior. Angew Chem Int Ed Engl 2021; 60:25020-25027. [PMID: 34534391 DOI: 10.1002/anie.202110185] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Indexed: 12/18/2022]
Abstract
Adding ferromagnetism into semiconductors attracts much attentions due to its potential usage of magnetic spins in novel devices, such as spin field-effect transistors. However, it remains challenging to stabilize their ferromagnetism above room temperature. Here we introduce an atomic chemical-solution strategy to grow wafer-size NiO thin films with controllable thickness down to sub-nanometer scale (0.92 nm) for the first time. Surface lattice defects break the magnetic symmetry of NiO and produce surface ferromagnetic behaviors. Our sub-nanometric NiO thin film exhibits the highest reported room-temperature ferromagnetic behavior with a saturation magnetization of 157 emu/cc and coercivity of 418 Oe. Attributed to wafer size, the easily-transferred NiO thin film is further verified in a magnetoresistance device. Our work provides a sub-nanometric platform to produce wafer-size ferromagnetic NiO thin films as atomic layer magnetic units in future transparent magnetoelectric devices.
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Affiliation(s)
- Jiong Wang
- College of Energy, Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province & Key Lab of Modern Optical Technologies of Education Ministry of China, Soochow University, Suzhou, 215123, China
| | - Liang Ma
- College of Energy, Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province & Key Lab of Modern Optical Technologies of Education Ministry of China, Soochow University, Suzhou, 215123, China
| | - Xiangyi Wang
- College of Energy, Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province & Key Lab of Modern Optical Technologies of Education Ministry of China, Soochow University, Suzhou, 215123, China
| | - Xiaohan Wang
- College of Energy, Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province & Key Lab of Modern Optical Technologies of Education Ministry of China, Soochow University, Suzhou, 215123, China
| | - Junjie Yao
- College of Energy, Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province & Key Lab of Modern Optical Technologies of Education Ministry of China, Soochow University, Suzhou, 215123, China
| | - Qinghua Yi
- College of Energy, Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province & Key Lab of Modern Optical Technologies of Education Ministry of China, Soochow University, Suzhou, 215123, China
| | - Rujun Tang
- School of Physical Science and Technology, Jiangsu Key Laboratory of Thin Films, Soochow University, Suzhou, 215123, China
| | - Guifu Zou
- College of Energy, Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province & Key Lab of Modern Optical Technologies of Education Ministry of China, Soochow University, Suzhou, 215123, China
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11
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Srivastava S, Thomas JP, Guan X, Leung KT. Induced Complementary Resistive Switching in Forming-Free TiO x/TiO 2/TiO x Memristors. ACS APPLIED MATERIALS & INTERFACES 2021; 13:43022-43029. [PMID: 34463478 DOI: 10.1021/acsami.1c09775] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The undesirable sneak current path is one of the key challenges in high-density memory integration for the emerging cross-bar memristor arrays. This work demonstrates a new heterojunction design of oxide multilayer stacking with different oxygen vacancy contents to manipulate the oxidation state. We show that the bipolar resistive switching (BRS) behavior of the Pt/TiOx/Pt cross-bar structure can be changed to complementary resistive switching (CRS) by introducing a thin TiO2 layer in the middle of the TiOx layer to obtain a Pt/TiOx/TiO2/TiOx/Pt device architecture with a double-junction active matrix. In contrast to the BRS in a single-layer TiOx matrix, the device with a double-junction matrix remains in a high-resistance state in the voltage range below the SET voltage, which makes it an efficient structure to overcome the sneak path constraints of undesired half-selected cells that lead to incorrect output reading. This architecture is capable of eliminating these half-selected cells between the nearby cross-bar cells in a smaller programming voltage range. A simplified model for the switching mechanism can be used to account for the observed high-quality switching performance with excellent endurance and current retention properties.
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Affiliation(s)
- Saurabh Srivastava
- WATLab and Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
- Low Energy Electronics System (LEES), Singapore MIT Alliance for Research and Technology (SMART), 1 Create Way, Singapore 138602, Singapore
| | - Joseph Palathinkal Thomas
- WATLab and Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
| | - Xiaoyi Guan
- WATLab and Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
| | - Kam Tong Leung
- WATLab and Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
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12
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Liu N, Cao Y, Zhu YL, Wang YJ, Tang YL, Wu B, Zou MJ, Feng YP, Ma XL. Spinodal Decomposition-Driven Endurable Resistive Switching in Perovskite Oxides. ACS APPLIED MATERIALS & INTERFACES 2021; 13:31001-31009. [PMID: 34156226 DOI: 10.1021/acsami.1c06649] [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
Common pursuits of developing nanometric logic and neuromorphic applications have motivated intensive research studies into low-dimensional resistive random-access memory (RRAM) materials. However, fabricating resistive switching medium with inherent stability and homogeneity still remains a bottleneck. Herein, we report a self-assembled uniform biphasic system, comprising low-resistance 3 nm-wide (Bi0.4,La0.6)FeO3-δ nanosheets coherently embedded in a high-resistance (Bi0.2,La0.8)FeO3-δ matrix, which were spinodally decomposed from an overall stoichiometry of the (Bi0.24,La0.76)FeO3-δ parent phase, as a promising nanocomposite to be a stable and endurable RRAM medium. The Bi-rich nanosheets accommodating high concentration of oxygen vacancies as corroborated by X-ray photoelectron spectroscopy and electron energy loss spectroscopy function as fast carrier channels, thus enabling an intrinsic electroforming-free character. Surficial electrical state and resistive switching properties are investigated using multimodal scanning probe microscopy techniques and macroscopic I-V measurements, showing high on/off ratio (∼103) and good endurance (up to 1.6 × 104 cycles). The established spinodal decomposition-driven phase-coexistence BLFO system demonstrates the merits of stability, uniformity, and endurability, which is promising for further application in RRAM devices.
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Affiliation(s)
- Nan Liu
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
- School of Material Science and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Yi Cao
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
- School of Material Science and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Yin-Lian Zhu
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
| | - Yu-Jia Wang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
| | - Yun-Long Tang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
| | - Bo Wu
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Min-Jie Zou
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Yan-Peng Feng
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xiu-Liang Ma
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
- State Key Lab of Advanced Processing and Recycling on Non-ferrous Metals, Lanzhou University of Technology, Langongping Road 287, Lanzhou 730050, China
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13
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Yun C, Li W, Gao X, Dou H, Maity T, Sun X, Wu R, Peng Y, Yang J, Wang H, MacManus-Driscoll JL. Creating Ferromagnetic Insulating La 0.9Ba 0.1MnO 3 Thin Films by Tuning Lateral Coherence Length. ACS APPLIED MATERIALS & INTERFACES 2021; 13:8863-8870. [PMID: 33586975 PMCID: PMC8023513 DOI: 10.1021/acsami.1c00607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 01/28/2021] [Indexed: 06/12/2023]
Abstract
In this work, heteroepitaxial vertically aligned nanocomposite (VAN) La0.9Ba0.1MnO3 (LBMO)-CeO2 films are engineered to produce ferromagnetic insulating (FMI) films. From combined X-ray photoelectron spectroscopy, X-ray diffraction, and electron microscopy, the elimination of the insulator-metal (I-M) transition is shown to result from the creation of very small lateral coherence lengths (with the corresponding lateral size ∼ 3 nm (∼7 u.c.)) in the LBMO matrix, achieved by engineering a high density of CeO2 nanocolumns in the matrix. The small lateral coherence length leads to a shift in the valence band maximum and reduction of the double exchange (DE) coupling. There is no "dead layer" effect at the smallest achieved lateral coherence length of ∼3 nm. The FMI behavior obtained by lateral dimensional tuning is independent of substrate interactions, thus intrinsic to the film itself and hence not related to film thickness. The unique properties of VAN films give the possibility for multilayer spintronic devices that can be made without interface degradation effects between the layers.
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Affiliation(s)
- Chao Yun
- Department
of Materials Science and Metallurgy, University
of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, United Kingdom
- State
Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Weiwei Li
- Department
of Materials Science and Metallurgy, University
of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, United Kingdom
| | - Xingyao Gao
- Materials
Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Hongyi Dou
- Materials
Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Tuhin Maity
- Department
of Materials Science and Metallurgy, University
of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, United Kingdom
- School
of Physics, Indian Institute of Science
Education and Research Thiruvananthapuram, Thiruvananthapuram, Kerala 695551, India
| | - Xing Sun
- Materials
Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Rui Wu
- Department
of Materials Science and Metallurgy, University
of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, United Kingdom
| | - Yuxuan Peng
- State
Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Jinbo Yang
- State
Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Haiyan Wang
- Materials
Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Judith L. MacManus-Driscoll
- Department
of Materials Science and Metallurgy, University
of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, United Kingdom
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14
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Huang J, Zhang D, Qi Z, Zhang B, Wang H. Hybrid Ag-LiNbO 3 nanocomposite thin films with tailorable optical properties. NANOSCALE ADVANCES 2021; 3:1121-1126. [PMID: 36133298 PMCID: PMC9417351 DOI: 10.1039/d0na00975j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 12/28/2020] [Indexed: 06/16/2023]
Abstract
Ag nanostructures exhibit extraordinary optical properties, which are important for photonic device integration. Herein, we deposited Ag-LiNbO3 (LNO) nanocomposite thin films with Ag nanoparticles (NPs) embedded into the LNO matrix by the co-deposition of Ag and LNO using a pulsed laser deposition (PLD) method. The density and size of Ag NPs were tailored by varying the Ag composition. Low-density and high-density Ag-LNO nanocomposite thin films were deposited and their optical properties, such as transmittance spectra, ellipsometry measurement, as well as angle-dependent and polarization-resolved reflectivity spectra, were explored. The Ag-LNO films show surface plasmon resonance (SPR) in the visible range, tunable optical constants and optical anisotropy, which are critical for photonic device applications.
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Affiliation(s)
- Jijie Huang
- School of Materials, Sun Yat-sen University Guangzhou Guangdong 510275 China
| | - Di Zhang
- School of Materials Engineering, Purdue University West Lafayette IN 47907 USA
| | - Zhimin Qi
- School of Materials Engineering, Purdue University West Lafayette IN 47907 USA
| | - Bruce Zhang
- School of Electrical and Computer Engineering, Purdue University West Lafayette IN 47907 USA
| | - Haiyan Wang
- School of Materials Engineering, Purdue University West Lafayette IN 47907 USA
- School of Electrical and Computer Engineering, Purdue University West Lafayette IN 47907 USA
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15
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Mühlenbein L, Singh CB, Lotnyk A, Himcinschi C, Yun Y, Ramakrishnegowda N, Knoche DS, Li X, Bhatnagar A. Nanocomposites with Three-Dimensional Architecture and Impact on Photovoltaic Effect. NANO LETTERS 2020; 20:8789-8795. [PMID: 33253587 DOI: 10.1021/acs.nanolett.0c03654] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We demonstrate the synthesis of self-assembled three-dimensional nanocomposite thin films consisting of NiO nanocolumns in an layered Aurivillius phase matrix. The structures were grown on single-crystal SrTiO3 substrates via pulsed laser deposition (PLD) with single ceramic (PbTiO3)x(BiNi2/3Nb1/3O3)1-x targets. The nanocolumns, which are about 10 nm in diameter each, extend over the entire film thickness of up to 225 nm. We reveal the difference in electrical conduction properties of the nanocolumns and the surrounding matrix on the nanoscale via conductive atomic force microscopy. The nanocomposite thin films exhibit improved photovoltaic performance compared to both pure PbTiO3 and homogeneous Aurivillius phase thin films.
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Affiliation(s)
- Lutz Mühlenbein
- Zentrum für Innovationskompetenz SiLi-nano, Martin Luther Universität Halle-Wittenberg, Halle (Saale) 06120, Germany
- Institute of Physics, Martin Luther Universität Halle-Wittenberg, Halle (Saale) 06120, Germany
| | - Chandra Bhal Singh
- Indian Institute of Technology, Banaras Hindu University, Varanasi 221005, India
| | - Andriy Lotnyk
- Leibniz Institute of Surface Engineering, Leipzig 04318, Germany
- Laboratory of Infrared Materials and Devices, The Research Institute of Advanced Technologies, Ningbo University, Ningbo 315211, China
| | - Cameliu Himcinschi
- Institute of Theoretical Physics, TU Bergakademie Freiberg, Freiberg D-09596, Germany
| | - Yeseul Yun
- Zentrum für Innovationskompetenz SiLi-nano, Martin Luther Universität Halle-Wittenberg, Halle (Saale) 06120, Germany
- Institute of Physics, Martin Luther Universität Halle-Wittenberg, Halle (Saale) 06120, Germany
| | - Niranjan Ramakrishnegowda
- Zentrum für Innovationskompetenz SiLi-nano, Martin Luther Universität Halle-Wittenberg, Halle (Saale) 06120, Germany
- Institute of Physics, Martin Luther Universität Halle-Wittenberg, Halle (Saale) 06120, Germany
| | - David S Knoche
- Zentrum für Innovationskompetenz SiLi-nano, Martin Luther Universität Halle-Wittenberg, Halle (Saale) 06120, Germany
- Institute of Physics, Martin Luther Universität Halle-Wittenberg, Halle (Saale) 06120, Germany
| | - Xinye Li
- Zentrum für Innovationskompetenz SiLi-nano, Martin Luther Universität Halle-Wittenberg, Halle (Saale) 06120, Germany
- Institute of Physics, Martin Luther Universität Halle-Wittenberg, Halle (Saale) 06120, Germany
| | - Akash Bhatnagar
- Zentrum für Innovationskompetenz SiLi-nano, Martin Luther Universität Halle-Wittenberg, Halle (Saale) 06120, Germany
- Institute of Physics, Martin Luther Universität Halle-Wittenberg, Halle (Saale) 06120, Germany
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16
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Enriquez E, Li Q, Bowlan P, Lu P, Zhang B, Li L, Wang H, Taylor AJ, Yarotski D, Prasankumar RP, Kalinin SV, Jia Q, Chen A. Induced ferroelectric phases in SrTiO 3 by a nanocomposite approach. NANOSCALE 2020; 12:18193-18199. [PMID: 32856672 DOI: 10.1039/d0nr03460f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Inducing new phases in thick films via vertical lattice strain is one of the critical advantages of vertically aligned nanocomposites (VANs). In SrTiO3 (STO), the ground state is ferroelastic, and the ferroelectricity in STO is suppressed by the orthorhombic transition. Here, we explore whether vertical lattice strain in three-dimensional VANs can be used to induce new ferroelectric phases in SrTiO3:MgO (STO:MgO) VAN thin films. The STO:MgO system incorporates ordered, vertically aligned MgO nanopillars into a STO film matrix. Strong lattice coupling between STO and MgO imposes a large lattice strain in the STO film. We have investigated ferroelectricity in the STO phase, existing up to room temperature, using piezoresponse force microscopy, phase field simulation and second harmonic generation. We also serendipitously discovered the formation of metastable TiO nanocores in MgO nanopillars embedded in the STO film matrix. Our results emphasize the design of new phases via vertical epitaxial strain in VAN thin films.
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Affiliation(s)
- Erik Enriquez
- Center for Integrated Nanotechnologies (CINT), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
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17
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Srivastava S, Thomas JP, Leung KT. Programmable, electroforming-free TiO x/TaO x heterojunction-based non-volatile memory devices. NANOSCALE 2019; 11:18159-18168. [PMID: 31556429 DOI: 10.1039/c9nr06403f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Electroforming-free resistive switching in memristors is essential to reliably achieving the performance of high switching speed, high endurance, good signal retention, and low power consumption expected for next-generation computing devices. Although there have been various approaches to resolve the issues observed with the electroforming process in oxide-based memory devices, most of them end up having high SET and RESET voltages and short lifetimes. We present a heterojunction interface of oxygen-vacancy-defect-rich ultrananocrystalline TiOx and TaOx films used as the switching matrix, which enables high-quality electroforming-free switching with a much lower programming voltage (+0.5-0.8 V), a high endurance of over 104 cycles and good retention performance with an estimated device lifetime of over 10 years. The electroforming-free switching behavior is governed by migration of oxygen vacancies driven by electric field localization that is imposed by the ultrananocrystalline nature of the TaOx film, serving as the switching matrix, with the TiOx film serving as an additional oxygen vacancy source to reduce the overall resistivity of TaOx and provide low-bias rectification. The ability to perform electroforming-free resistive switching along with excellent switching repeatability and retention capabilities for various digital and analog programmable voltages enables high scalability and large density integration of the cross-bar ReRAM framework.
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Affiliation(s)
- Saurabh Srivastava
- WATLab and Department of Chemistry, University of Waterloo, 200 University Ave. W., Waterloo, Ontario N2L 3G1, Canada.
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18
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Chen K, Li L. Ordered Structures with Functional Units as a Paradigm of Material Design. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1901115. [PMID: 31199019 DOI: 10.1002/adma.201901115] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 03/28/2019] [Indexed: 05/22/2023]
Abstract
Realizing new functions through the construction of ordered structures not only exists naturally in nature, but also in artificial materials. However, much research focuses more on the relationship between structure and performance rather than on the impact of functional units themselves. Reviewing previous research findings, a "paradigm" of material research is proposed, which is based on ordered structures with functional units (OSFU) such as compositions, phases, domains, and twins. The goal is to draw more intensive attention of researchers to this concept and thus to promote the development of this field toward a deeper and broader direction, producing highly influential research results.
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Affiliation(s)
- Kexin Chen
- Department of Engineering and Material Sciences, National Natural Science Foundation of China (NSFC), Beijing, 100085, P. R. China
| | - Liang Li
- Department of Engineering and Material Sciences, National Natural Science Foundation of China (NSFC), Beijing, 100085, P. R. China
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19
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Nallagatla VR, Jo J, Acharya SK, Kim M, Jung CU. Confining vertical conducting filament for reliable resistive switching by using a Au-probe tip as the top electrode for epitaxial brownmillerite oxide memristive device. Sci Rep 2019; 9:1188. [PMID: 30718689 PMCID: PMC6362224 DOI: 10.1038/s41598-018-37986-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 12/03/2018] [Indexed: 11/09/2022] Open
Abstract
We had discovered novel resistance switching phenomena in SrCoOx epitaxial thin films. We have interpreted the results in terms of the topotactic phase transformation between their insulating brownmillerite phase and the conducting perovskite phase and the existence of a rather vertical conducting filament due to its inherent layered structure. However, the rough interface observed between the SrCoOx and the Au top electrode (area ~10000 μm2) was assumed to result in the observed fluctuation in key switching parameters. In order to verify the effect of rough interface on the switching performance in the SrCoOx device, in this work, we studied the resistive switching properties of a SrCoOx device by placing a Au-coated tip (end area ~0.5 μm2) directly on the film surface as the top electrode. The resulting device displayed much improved endurance and showed high uniformity in key switching parameters as compared to the device having a large top electrode area. A simulation result confirmed that the Au-coated tip provides a local confinement of the electrical field, resulting in confinement of oxygen ion distribution and therefore localization of the conducting filament. By minimizing other free and uncontrollable parameters, the designed experiment here provides the most direct and isolated evidence that the rough interface between electrode and ReRAM matrix is detrimental for the reproducibility of resistivity switching phenomena.
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Affiliation(s)
| | - Janghyun Jo
- Department of Material Science and Engineering and Research Institute of Advanced Materials, Seoul National University, Seoul, 151-747, Korea
| | - Susant Kumar Acharya
- Department of Physics and Oxide Research Center, Hankuk University of Foreign Studies, Yongin, 449-791, Korea
| | - Miyoung Kim
- Department of Material Science and Engineering and Research Institute of Advanced Materials, Seoul National University, Seoul, 151-747, Korea
| | - Chang Uk Jung
- Department of Physics and Oxide Research Center, Hankuk University of Foreign Studies, Yongin, 449-791, Korea.
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20
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Chen A, Su Q, Han H, Enriquez E, Jia Q. Metal Oxide Nanocomposites: A Perspective from Strain, Defect, and Interface. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1803241. [PMID: 30368932 DOI: 10.1002/adma.201803241] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 08/13/2018] [Indexed: 06/08/2023]
Abstract
Vertically aligned nanocomposite thin films with ordered two phases, grown epitaxially on substrates, have attracted tremendous interest in the past decade. These unique nanostructured composite thin films with large vertical interfacial area, controllable vertical lattice strain, and defects provide an intriguing playground, allowing for the manipulation of a variety of functional properties of the materials via the interplay among strain, defect, and interface. This field has evolved from basic growth and characterization to functionality tuning as well as potential applications in energy conversion and information technology. Here, the remarkable progress achieved in vertically aligned nanocomposite thin films from a perspective of tuning functionalities through control of strain, defect, and interface is summarized.
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Affiliation(s)
- Aiping Chen
- Center for Integrated Nanotechnologies (CINT), Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Qing Su
- Nebraska Center for Energy Sciences Research, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA
| | - Hyungkyu Han
- Center for Integrated Nanotechnologies (CINT), Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Erik Enriquez
- Center for Integrated Nanotechnologies (CINT), Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Quanxi Jia
- Department of Materials Design and Innovation, University at Buffalo-The State University of New York, Buffalo, NY, 14260, USA
- Division of Quantum Phases and Devices, Department of Physics, Konkuk University, Seoul, 143-701, South Korea
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21
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Huang J, Qi Z, Li L, Wang H, Xue S, Zhang B, Zhang X, Wang H. Self-assembled vertically aligned Ni nanopillars in CeO 2 with anisotropic magnetic and transport properties for energy applications. NANOSCALE 2018; 10:17182-17188. [PMID: 30191234 DOI: 10.1039/c8nr05532g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Self-assembled vertically aligned metal-oxide (Ni-CeO2) nanocomposite thin films with novel multifunctionalities have been successfully deposited by a one-step growth method. The novel nanocomposite structures presents high-density Ni-nanopillars vertically aligned in a CeO2 matrix. Strong and anisotropic magnetic properties have been demonstrated, with a saturation magnetization (Ms) of ∼175 emu cm-3 and ∼135 emu cm-3 for out-of-plane and in-plane directions, respectively. Such unique vertically aligned ferromagnetic Ni nanopillars in the CeO2 matrix have been successfully incorporated in high temperature superconductor YBa2Cu3O7 (YBCO) coated conductors as effective magnetic flux pinning centers. The highly anisotropic nanostructures with high density vertical interfaces between the Ni nanopillars and CeO2 matrix also promote the mixed electrical and ionic conductivities out-of-plane and thus demonstrate great potential as nanocomposite anode materials for solid oxide fuel cells and other potential applications requiring anisotropic ionic transport properties.
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Affiliation(s)
- Jijie Huang
- School of Materials Engineering, Purdue University, West Lafayette, IN, 47906 USA.
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22
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Sangle AL, Lee OJ, Kursumovic A, Zhang W, Chen A, Wang H, MacManus-Driscoll JL. Very high commutation quality factor and dielectric tunability in nanocomposite SrTiO 3 thin films with T c enhanced to >300 °C. NANOSCALE 2018; 10:3460-3468. [PMID: 29446777 PMCID: PMC5815283 DOI: 10.1039/c7nr06991j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 11/10/2017] [Indexed: 05/13/2023]
Abstract
We report on nanoengineered SrTiO3-Sm2O3 nanocomposite thin films with the highest reported values of commutation quality factor (CQF or K-factor) of >2800 in SrTiO3 at room temperature. The films also had a large tunability of dielectric constant (49%), low tangent loss (tan δ = 0.01) and a Curie temperature for SrTiO3 > 300 °C, making them very attractive for tunable RF applications. The enhanced properties originate from the unique nanostructure in the films, with <20 nm diameter strain-controlling Sm2O3 nanocolumns embedded in a SrTiO3 matrix. Very large out-of-plane strains (up to 2.6%) and high tetragonality (c/a) (up to 1.013) were induced in the SrTiO3. The K-factor was further enhanced by adding 1 at% Sc3+ (acceptor) dopant in SrTiO3 to a value of 3300 with the tangent loss being ≤0.01 up to 1000 kV cm-1.
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Affiliation(s)
- Abhijeet L. Sangle
- Department of Materials Science and Metallurgy , University of Cambridge , UK . ;
| | - Oon Jew Lee
- School of Fundamental Science , Universiti Malaysia Terengganu , 21300 Kuala Terengganu , Malaysia
| | - Ahmed Kursumovic
- Department of Materials Science and Metallurgy , University of Cambridge , UK . ;
| | - Wenrui Zhang
- Center for Functional Nanomaterials , Brookhaven National Laboratory , Bldg. 735 – P.O. Box 5000 , Upton , NY 11973-5000 , USA
| | - Aiping Chen
- Center for Integrated Nanotechnologies (CINT) , Los Alamos National Laboratory , Los Alamos , NM 87545 , USA
| | - Haiyan Wang
- School of Materials Engineering , Purdue University , West Lafayette , IN 47907 , USA
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23
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Scalable lattice-strain in preferentially oriented acceptor-doped cerium oxide film and its impact on oxygen ion transport kinetics. Electrochim Acta 2018. [DOI: 10.1016/j.electacta.2018.01.097] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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24
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Srivastava S, Thomas JP, Heinig NF, Leung KT. High-Performance Single-Active-Layer Memristor Based on an Ultrananocrystalline Oxygen-Deficient TiO x Film. ACS APPLIED MATERIALS & INTERFACES 2017; 9:36989-36996. [PMID: 28975787 DOI: 10.1021/acsami.7b07971] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The theoretical and practical realization of memristive devices has been hailed as the next step for nonvolatile memories, low-power remote sensing, and adaptive intelligent prototypes for neuromorphic and biological systems. However, the active materials of currently available memristors need to undergo an often destructive high-bias electroforming process in order to activate resistive switching. This limits their device performance in switching speed, endurance/retention, and power consumption upon high-density integration, due to excessive Joule heating. By employing a nanocrystalline oxygen-deficient TiOx switching matrix to localize the electric field at discrete locations, it is possible to resolve the Joule heating problem by reducing the need for electroforming at high bias. With a Pt/TiOx/Pt stacking architecture, our device follows an electric field driven, vacancy-modulated interface-type switching that is sensitive to the junction size. By scaling down the junction size, the SET voltage and output current can be reduced, and a SET voltage as low as +0.59 V can be obtained for a 5 × 5 μm2 junction size. Along with its potentially fast switching (over 105 cycles with a 100 μs voltage pulse) and high retention (over 105 s) performance, memristors based on these disordered oxygen-deficient TiOx films promise viable building blocks for next-generation nonvolatile memories and other logic circuit systems.
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Affiliation(s)
- Saurabh Srivastava
- WATLab and Department of Chemistry, University of Waterloo , Waterloo, Ontario N2L3G1, Canada
| | - Joseph P Thomas
- WATLab and Department of Chemistry, University of Waterloo , Waterloo, Ontario N2L3G1, Canada
| | - Nina F Heinig
- WATLab and Department of Chemistry, University of Waterloo , Waterloo, Ontario N2L3G1, Canada
| | - K T Leung
- WATLab and Department of Chemistry, University of Waterloo , Waterloo, Ontario N2L3G1, Canada
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25
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Acharya SK, Jo J, Raveendra NV, Dash U, Kim M, Baik H, Lee S, Park BH, Lee JS, Chae SC, Hwang CS, Jung CU. Brownmillerite thin films as fast ion conductors for ultimate-performance resistance switching memory. NANOSCALE 2017; 9:10502-10510. [PMID: 28708191 DOI: 10.1039/c7nr04011c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
An oxide-based resistance memory is a leading candidate to replace Si-based flash memory as it meets the emerging specifications for future memory devices. The non-uniformity in the key switching parameters and low endurance in conventional resistance memory devices are preventing its practical application. Here, a novel strategy to overcome the aforementioned challenges has been unveiled by tuning the growth direction of epitaxial brownmillerite SrFeO2.5 thin films along the SrTiO3 [111] direction so that the oxygen vacancy channels can connect both the top and bottom electrodes rather directly. The controlled oxygen vacancy channels help reduce the randomness of the conducting filament (CF). The resulting device displayed high endurance over 106 cycles, and a short switching time of ∼10 ns. In addition, the device showed very high uniformity in the key switching parameters for device-to-device and within a device. This work demonstrates a feasible example for improving the nanoscale device performance by controlling the atomic structure of a functional oxide layer.
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Affiliation(s)
- Susant Kumar Acharya
- Department of Physics and Oxide Research Centre, Hankuk University of Foreign Studies, Yongin 449-791, Republic of Korea.
| | - Janghyun Jo
- Department of Material Science and Engineering and Research Institute of Advanced Materials, Seoul National University, Seoul 151-747, Republic of Korea
| | - Nallagatlla Venkata Raveendra
- Department of Physics and Oxide Research Centre, Hankuk University of Foreign Studies, Yongin 449-791, Republic of Korea.
| | - Umasankar Dash
- Department of Physics and Oxide Research Centre, Hankuk University of Foreign Studies, Yongin 449-791, Republic of Korea.
| | - Miyoung Kim
- Department of Material Science and Engineering and Research Institute of Advanced Materials, Seoul National University, Seoul 151-747, Republic of Korea
| | - Hionsuck Baik
- Division of Analytical Research, Korea Basic Science Institute, 74 Inchon-ro, Sungbuk-gu, Seoul 136-713, Republic of Korea
| | - Sangik Lee
- Department of Physics and Division of Quantum Phases and Devices, Konkuk University, Seoul 143-791, Republic of Korea
| | - Bae Ho Park
- Department of Physics and Division of Quantum Phases and Devices, Konkuk University, Seoul 143-791, Republic of Korea
| | - Jae Sung Lee
- Quantum Universe Centre, Korea Institute for Advanced Study, Seoul 02455, Republic of Korea
| | - Seung Chul Chae
- Department of Physics Education, Seoul National University, Seoul 08826, Republic of Korea
| | - Cheol Seong Hwang
- Department of Materials Science and Engineering and Inter-University Semiconductor Research Center, Seoul National University, Seoul 151-744, Republic of Korea.
| | - Chang Uk Jung
- Department of Physics and Oxide Research Centre, Hankuk University of Foreign Studies, Yongin 449-791, Republic of Korea.
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26
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Cho S, Yun C, Tappertzhofen S, Kursumovic A, Lee S, Lu P, Jia Q, Fan M, Jian J, Wang H, Hofmann S, MacManus-Driscoll JL. Self-assembled oxide films with tailored nanoscale ionic and electronic channels for controlled resistive switching. Nat Commun 2016; 7:12373. [PMID: 27491392 PMCID: PMC4980456 DOI: 10.1038/ncomms12373] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 06/24/2016] [Indexed: 11/09/2022] Open
Abstract
Resistive switches are non-volatile memory cells based on nano-ionic redox processes that offer energy efficient device architectures and open pathways to neuromorphics and cognitive computing. However, channel formation typically requires an irreversible, not well controlled electroforming process, giving difficulty to independently control ionic and electronic properties. The device performance is also limited by the incomplete understanding of the underlying mechanisms. Here, we report a novel memristive model material system based on self-assembled Sm-doped CeO2 and SrTiO3 films that allow the separate tailoring of nanoscale ionic and electronic channels at high density (∼10(12) inch(-2)). We systematically show that these devices allow precise engineering of the resistance states, thus enabling large on-off ratios and high reproducibility. The tunable structure presents an ideal platform to explore ionic and electronic mechanisms and we expect a wide potential impact also on other nascent technologies, ranging from ionic gating to micro-solid oxide fuel cells and neuromorphics.
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Affiliation(s)
- Seungho Cho
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, UK
| | - Chao Yun
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, UK
| | - Stefan Tappertzhofen
- Department of Engineering, University of Cambridge, 9 J.J. Thomson Avenue, Cambridge CB3 0FA, UK
| | - Ahmed Kursumovic
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, UK
| | - Shinbuhm Lee
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, UK
| | - Ping Lu
- Sandia National Laboratory, Albuquerque, New Mexico 87185, USA
| | - Quanxi Jia
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Meng Fan
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas 77843, USA
| | - Jie Jian
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas 77843, USA
| | - Haiyan Wang
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas 77843, USA
- School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907, USA
| | - Stephan Hofmann
- Department of Engineering, University of Cambridge, 9 J.J. Thomson Avenue, Cambridge CB3 0FA, UK
| | - Judith L. MacManus-Driscoll
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, UK
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27
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Chen A, Hu JM, Lu P, Yang T, Zhang W, Li L, Ahmed T, Enriquez E, Weigand M, Su Q, Wang H, Zhu JX, MacManus-Driscoll JL, Chen LQ, Yarotski D, Jia Q. Role of scaffold network in controlling strain and functionalities of nanocomposite films. SCIENCE ADVANCES 2016; 2:e1600245. [PMID: 27386578 PMCID: PMC4928986 DOI: 10.1126/sciadv.1600245] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 05/19/2016] [Indexed: 05/26/2023]
Abstract
Strain is a novel approach to manipulating functionalities in correlated complex oxides. However, significant epitaxial strain can only be achieved in ultrathin layers. We show that, under direct lattice matching framework, large and uniform vertical strain up to 2% can be achieved to significantly modify the magnetic anisotropy, magnetism, and magnetotransport properties in heteroepitaxial nanoscaffold films, over a few hundred nanometers in thickness. Comprehensive designing principles of large vertical strain have been proposed. Phase-field simulations not only reveal the strain distribution but also suggest that the ultimate strain is related to the vertical interfacial area and interfacial dislocation density. By changing the nanoscaffold density and dimension, the strain and the magnetic properties can be tuned. The established correlation among the vertical interface-strain-properties in nanoscaffold films can consequently be used to tune other functionalities in a broad range of complex oxide films far beyond critical thickness.
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Affiliation(s)
- Aiping Chen
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Jia-Mian Hu
- Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802, USA
| | - Ping Lu
- Sandia National Laboratories, Mail Stop 1411, Albuquerque, NM 87185, USA
| | - Tiannan Yang
- Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802, USA
| | - Wenrui Zhang
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Leigang Li
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Towfiq Ahmed
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Erik Enriquez
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Marcus Weigand
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Qing Su
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Haiyan Wang
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Jian-Xin Zhu
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | | | - Long-Qing Chen
- Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802, USA
| | - Dmitry Yarotski
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Quanxi Jia
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
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28
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Sun Z, Zhao Y, He M, Gu L, Ma C, Jin K, Zhao D, Luo N, Zhang Q, Wang N, Duan W, Nan CW. Deterministic Role of Concentration Surplus of Cation Vacancy over Anion Vacancy in Bipolar Memristive NiO. ACS APPLIED MATERIALS & INTERFACES 2016; 8:11583-11591. [PMID: 27096884 DOI: 10.1021/acsami.6b01400] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Migration of oxygen vacancies has been proposed to play an important role in the bipolar memristive behaviors because oxygen vacancies can directly determine the local conductivity in many systems. However, a recent theoretical work demonstrated that both migration of oxygen vacancies and coexistence of cation and anion vacancies are crucial to the occurrence of bipolar memristive switching, normally observed in the small-sized NiO. So far, experimental work addressing this issue is still lacking. In this work, with conductive atomic force microscopy and combined scanning transmission electron microscopy and electron energy loss spectroscopy, we reveal that concentration surplus of Ni vacancy over O vacancy determines the bipolar memristive switching of NiO films. Our work supports the dual-defects-based model, which is of fundamental importance for understanding the memristor mechanisms beyond the well-established oxygen-vacancy-based model. Moreover, this work provides a methodology to investigate the effect of dual defects on memristive behaviors.
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Affiliation(s)
- Zhong Sun
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University , Beijing 100084, China
- Collaborative Innovation Center of Quantum Matter , Beijing 100084, China
| | - Yonggang Zhao
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University , Beijing 100084, China
- Collaborative Innovation Center of Quantum Matter , Beijing 100084, China
| | - Min He
- Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences , Beijing 100190, China
| | - Lin Gu
- Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences , Beijing 100190, China
- Collaborative Innovation Center of Quantum Matter , Beijing 100084, China
| | - Chao Ma
- Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences , Beijing 100190, China
| | - Kuijuan Jin
- Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences , Beijing 100190, China
- Collaborative Innovation Center of Quantum Matter , Beijing 100084, China
| | - Diyang Zhao
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University , Beijing 100084, China
- Collaborative Innovation Center of Quantum Matter , Beijing 100084, China
| | - Nannan Luo
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University , Beijing 100084, China
- Collaborative Innovation Center of Quantum Matter , Beijing 100084, China
| | - Qinghua Zhang
- State Key Lab of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University , Beijing 100084, China
| | - Na Wang
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University , Beijing 100084, China
- Collaborative Innovation Center of Quantum Matter , Beijing 100084, China
| | - Wenhui Duan
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University , Beijing 100084, China
- Collaborative Innovation Center of Quantum Matter , Beijing 100084, China
| | - Ce-Wen Nan
- State Key Lab of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University , Beijing 100084, China
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29
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He B, Wang Z. Enhancement of the Electrical Properties in BaTiO3/PbZr0.52Ti0.48O3 Ferroelectric Superlattices. ACS APPLIED MATERIALS & INTERFACES 2016; 8:6736-6742. [PMID: 26913563 DOI: 10.1021/acsami.5b12098] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In this study, BaTiO3/Pb(Zr0.52Ti0.48)O3 (BTO/PZT) ferroelectric superlattices have been grown on the Nb-doped SrTiO3 (NSTO) single-crystal substrate by pulsed laser deposition, and their electrical properties were investigated in detail. The leakage current was reduced significantly in the BTO/PZT superlattices, and the conduction mechanism could be interpreted as the bulk-limited mechanism. In addition, a more symmetric hysteresis loop was observed in the BTO/PZT superlattices compared with the pure PZT and BTO films. The BTO/PZT superlattices with the modulation thickness of 9.8 nm showed remarkably improved dielectric properties with dielectric constant and loss of 684 and 0.02, respectively, measured at the frequency of 10 kHz. Based on these experimental results, it can be considered that the BTO/PZT interfaces play a very important role for the enhanced electrical properties of the BTO/PZT superlattices.
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Affiliation(s)
- Bin He
- Shenyang National Laboratory for Materials Science, Institute of Metal Research (IMR), Chinese Academy of Sciences (CAS) , 72 Wenhua Road, Shenyang 110016, China
| | - Zhanjie Wang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research (IMR), Chinese Academy of Sciences (CAS) , 72 Wenhua Road, Shenyang 110016, China
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30
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Lee S, Zhang W, Khatkhatay F, Wang H, Jia Q, MacManus-Driscoll JL. Ionic Conductivity Increased by Two Orders of Magnitude in Micrometer-Thick Vertical Yttria-Stabilized ZrO2 Nanocomposite Films. NANO LETTERS 2015; 15:7362-7369. [PMID: 26335046 DOI: 10.1021/acs.nanolett.5b02726] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We design and create a unique cell geometry of templated micrometer-thick epitaxial nanocomposite films which contain ~20 nm diameter yttria-stabilized ZrO2 (YSZ) nanocolumns, strain coupled to a SrTiO3 matrix. The ionic conductivity of these nanocolumns is enhanced by over 2 orders of magnitude compared to plain YSZ films. Concomitant with the higher ionic conduction is the finding that the YSZ nanocolumns in the films have much higher crystallinity and orientation, compared to plain YSZ films. Hence, "oxygen migration highways" are formed in the desired out-of-plane direction. This improved structure is shown to originate from the epitaxial coupling of the YSZ nanocolumns to the SrTiO3 film matrix and from nucleation of the YSZ nanocolumns on an intermediate nanocomposite base layer of highly aligned Sm-doped CeO2 nanocolumns within the SrTiO3 matrix. This intermediate layer reduces the lattice mismatch between the YSZ nanocolumns and the substrate. Vertical ionic conduction values as high as 10(-2) Ω(-1) cm(-1) were demonstrated at 360 °C (300 °C lower than plain YSZ films), showing the strong practical potential of these nanostructured films for use in much lower operation temperature ionic devices.
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Affiliation(s)
- Shinbuhm Lee
- Department of Materials Science and Metallurgy, University of Cambridge , 27 Charles Babbage Road, Cambridge, CB3 0FS, United Kingdom
| | - Wenrui Zhang
- Department of Electrical and Computer Engineering, Texas A&M University , College Station, Texas 77843, United States
| | - Fauzia Khatkhatay
- Department of Electrical and Computer Engineering, Texas A&M University , College Station, Texas 77843, United States
| | - Haiyan Wang
- Department of Electrical and Computer Engineering, Texas A&M University , College Station, Texas 77843, United States
| | - Quanxi Jia
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
| | - Judith L MacManus-Driscoll
- Department of Materials Science and Metallurgy, University of Cambridge , 27 Charles Babbage Road, Cambridge, CB3 0FS, United Kingdom
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31
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Yang SM, Lee S, Jian J, Zhang W, Lu P, Jia Q, Wang H, Won Noh T, Kalinin SV, MacManus-Driscoll JL. Strongly enhanced oxygen ion transport through samarium-doped CeO2 nanopillars in nanocomposite films. Nat Commun 2015; 6:8588. [PMID: 26446866 PMCID: PMC4633963 DOI: 10.1038/ncomms9588] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 09/09/2015] [Indexed: 12/19/2022] Open
Abstract
Enhancement of oxygen ion conductivity in oxides is important for low-temperature (<500 °C) operation of solid oxide fuel cells, sensors and other ionotronic devices. While huge ion conductivity has been demonstrated in planar heterostructure films, there has been considerable debate over the origin of the conductivity enhancement, in part because of the difficulties of probing buried ion transport channels. Here we create a practical geometry for device miniaturization, consisting of highly crystalline micrometre-thick vertical nanocolumns of Sm-doped CeO2 embedded in supporting matrices of SrTiO3. The ionic conductivity is higher by one order of magnitude than plain Sm-doped CeO2 films. By using scanning probe microscopy, we show that the fast ion-conducting channels are not exclusively restricted to the interface but also are localized at the Sm-doped CeO2 nanopillars. This work offers a pathway to realize spatially localized fast ion transport in oxides of micrometre thickness.
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Affiliation(s)
- Sang Mo Yang
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 151-742, Korea
- Department of Physics and Astronomy, Seoul National University, Seoul 151-742, Korea
| | - Shinbuhm Lee
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, UK
| | - Jie Jian
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas 77843, USA
| | - Wenrui Zhang
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas 77843, USA
| | - Ping Lu
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - Quanxi Jia
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Haiyan Wang
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas 77843, USA
| | - Tae Won Noh
- Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 151-742, Korea
- Department of Physics and Astronomy, Seoul National University, Seoul 151-742, Korea
| | - Sergei V. Kalinin
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Judith L. MacManus-Driscoll
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, UK
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32
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Vertical Interface Induced Dielectric Relaxation in Nanocomposite (BaTiO3)1-x:(Sm2O3)x Thin Films. Sci Rep 2015; 5:11335. [PMID: 26061829 PMCID: PMC4462142 DOI: 10.1038/srep11335] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 05/22/2015] [Indexed: 11/13/2022] Open
Abstract
Vertical interfaces in vertically aligned nanocomposite thin films have been approved to be an effective method to manipulate functionalities. However, several challenges with regard to the understanding on the physical process underlying the manipulation still remain. In this work, because of the ordered interfaces and large interfacial area, heteroepitaxial (BaTiO3)1-x:(Sm2O3)x thin films have been fabricated and used as a model system to investigate the relationship between vertical interfaces and dielectric properties. Due to a relatively large strain generated at the interfaces, vertical interfaces between BaTiO3 and Sm2O3 are revealed to become the sinks to attract oxygen vacancies. The movement of oxygen vacancies is confined at the interfaces and hampered by the misfit dislocations, which contributed to a relaxation behavior in (BaTiO3)1-x:(Sm2O3)x thin films. This work represents an approach to further understand that how interfaces influence on dielectric properties in oxide thin films.
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