1
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Gao P, Duan M, Yang G, Zhang W, Jia C. Ultralow Energy Consumption and Fast Neuromorphic Computing Based on La 0.1Bi 0.9FeO 3 Ferroelectric Tunnel Junctions. NANO LETTERS 2024. [PMID: 39172999 DOI: 10.1021/acs.nanolett.4c01924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2024]
Abstract
Low-power and fast artificial neural network devices represent the direction in developing analogue neural networks. Here, an ultralow power consumption (0.8 fJ) and rapid (100 ns) La0.1Bi0.9FeO3/La0.7Sr0.3MnO3 ferroelectric tunnel junction artificial synapse has been developed to emulate the biological neural networks. The visual memory and forgetting functionalities have been emulated based on long-term potentiation and depression with good linearity. Moreover, with a single device, logical operations of "AND" and "OR" are implemented, and an artificial neural network was constructed with a recognition accuracy of 96%. Especially for noisy data sets, the recognition speed is faster after preprocessing by the device in the present work. This sets the stage for highly reliable and repeatable unsupervised learning.
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Affiliation(s)
- Pan Gao
- Henan Key Laboratory of Quantum Materials and Quantum Energy, School of Quantum Information Future Technology, Henan University, Kaifeng 475004, China
| | - Mengyuan Duan
- Henan Key Laboratory of Quantum Materials and Quantum Energy, School of Quantum Information Future Technology, Henan University, Kaifeng 475004, China
| | - Guanghong Yang
- Key Lab for Special Functional Materials of Ministry of Education, School of Materials, Henan University, Kaifeng 475004, P. R. China
| | - Weifeng Zhang
- Henan Key Laboratory of Quantum Materials and Quantum Energy, School of Quantum Information Future Technology, Henan University, Kaifeng 475004, China
- Institute of Quantum Materials and Physics, Henan Academy of Sciences, Zhengzhou 450046, China
| | - Caihong Jia
- Henan Key Laboratory of Quantum Materials and Quantum Energy, School of Quantum Information Future Technology, Henan University, Kaifeng 475004, China
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2
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Liu M, Wan TL, Dou K, Zhang L, Sun W, Jiang J, Ma Y, Gu Y, Kou L. Magnetic skyrmions and their manipulations in a 2D multiferroic CuCrP 2Te 6 monolayer. Phys Chem Chem Phys 2024; 26:6189-6195. [PMID: 38305045 DOI: 10.1039/d3cp05096c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2024]
Abstract
Magnetic skyrmions and their effective manipulations are promising for the design of next-generation information storage and processing devices, due to their topologically protected chiral spin textures and low energy cost. They, therefore, have attracted significant interest from the communities of condensed matter physics and materials science. Herein, based on density functional theory (DFT) calculations and micromagnetic simulations, we report the spontaneous 2 nm-diameter magnetic skyrmions in the monolayer CuCrP2Te6 originating from the synergistic effect of broken inversion symmetry and strong Dzyaloshinskii-Moriya interactions (DMIs). The creation and annihilation of magnetic skyrmions can be achieved via the ferroelectric to anti-ferroelectric (FE-to-AFE) transition, due to the variation of the magnetic parameter D2/|KJ|. Moreover, we also found that the DMIs and Heisenberg isotropic exchange can be manipulated by bi-axial strain, to effectively enhance skyrmion stability. Our findings provide feasible approaches to manipulate the skyrmions, which can be used for the design of next-generation information storage devices.
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Affiliation(s)
- Minghao Liu
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, QLD 4001, Australia.
| | - Tsz Lok Wan
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, QLD 4001, Australia.
| | - Kaiying Dou
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Shandanan Str. 27, Jinan 250100, P. R. China
| | - Lei Zhang
- School of Chemistry and Physics, Queensland University of Technology, Brisbane, QLD 4001, Australia
| | - Wei Sun
- Shandong Provincial Key Laboratory of Preparation and Measurement of Building Materials, University of Jinan, Jinan 250022, China
| | - Jiawei Jiang
- Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparation Technology, School of Science, Tianjin University, Tianjin 300354, China
| | - Yandong Ma
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Shandanan Str. 27, Jinan 250100, P. R. China
| | - Yuantong Gu
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, QLD 4001, Australia.
| | - Liangzhi Kou
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, QLD 4001, Australia.
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3
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Zhou T, Zhai T, Shen H, Wang J, Min R, Ma K, Zhang G. Strategies for enhancing performance of perovskite bismuth ferrite photocatalysts (BiFeO 3): A comprehensive review. CHEMOSPHERE 2023; 339:139678. [PMID: 37527742 DOI: 10.1016/j.chemosphere.2023.139678] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 07/08/2023] [Accepted: 07/28/2023] [Indexed: 08/03/2023]
Abstract
Organic pollutants pose a significant threat to water safety, and their degradation is of paramount importance. Photocatalytic technology has emerged as a promising approach for environmental remediation, and Bismuth ferrite (BiFeO3) has been shown to exhibit remarkable potential for photocatalytic degradation of water pollutants, with its excellent crystal structure properties and visible light photocatalytic activity. This review presents an overview of the crystal properties and photocatalytic mechanism of perovskite bismuth ferrite (BiFeO3), as well as a summary of various strategies for enhancing its efficiency in photocatalytic degradation of organic pollutants. These strategies include pure phase preparation, microscopic modulation, composite modification of BiFeO3, and the integration of Fenton-like reactions and external field-assisted methods to improve its photocatalytic performance. The review emphasizes the impact of each strategy on photocatalytic enhancement. By providing comprehensive strategies for improving the efficiency of BiFeO3 photocatalysis, this review inspires new insights for efficient degradation of organic pollutants using BiFeO3 photocatalysis and contributes to the development of photocatalysis in environmental remediation.
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Affiliation(s)
- Tianhong Zhou
- School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, China; Key Laboratory of Yellow River Water Environment in Gansu Province, Lanzhou Jiaotong University, Lanzhou, 730070, China
| | - Tianjiao Zhai
- School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, China; Key Laboratory of Yellow River Water Environment in Gansu Province, Lanzhou Jiaotong University, Lanzhou, 730070, China
| | - Huidong Shen
- School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, China; Key Laboratory of Yellow River Water Environment in Gansu Province, Lanzhou Jiaotong University, Lanzhou, 730070, China
| | - Jinyi Wang
- School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, China; Key Laboratory of Yellow River Water Environment in Gansu Province, Lanzhou Jiaotong University, Lanzhou, 730070, China
| | - Rui Min
- School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, China; Key Laboratory of Yellow River Water Environment in Gansu Province, Lanzhou Jiaotong University, Lanzhou, 730070, China
| | - Kai Ma
- School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, China; Key Laboratory of Yellow River Water Environment in Gansu Province, Lanzhou Jiaotong University, Lanzhou, 730070, China
| | - Guozhen Zhang
- School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, China; Key Laboratory of Yellow River Water Environment in Gansu Province, Lanzhou Jiaotong University, Lanzhou, 730070, China.
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4
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Continuously tunable ferroelectric domain width down to the single-atomic limit in bismuth tellurite. Nat Commun 2022; 13:5903. [PMID: 36202850 PMCID: PMC9537171 DOI: 10.1038/s41467-022-33617-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Accepted: 09/26/2022] [Indexed: 11/08/2022] Open
Abstract
Emerging functionalities in two-dimensional materials, such as ferromagnetism, superconductivity and ferroelectricity, open new avenues for promising nanoelectronic applications. Here, we report the discovery of intrinsic in-plane room-temperature ferroelectricity in two-dimensional Bi2TeO5 grown by chemical vapor deposition, where spontaneous polarization originates from Bi column displacements. We found an intercalated buffer layer consist of mixed Bi/Te column as 180° domain wall which enables facile polarized domain engineering, including continuously tunable domain width by pinning different concentration of buffer layers, and even ferroelectric-antiferroelectric phase transition when the polarization unit is pinned down to single atomic column. More interestingly, the intercalated Bi/Te buffer layer can interconvert to polarized Bi columns which end up with series terraced domain walls and unusual fan-shaped ferroelectric domain. The buffer layer induced size and shape tunable ferroelectric domain in two-dimensional Bi2TeO5 offer insights into the manipulation of functionalities in van der Waals materials for future nanoelectronics. Tunability of ferroelectric domain structure is significant in ferroelectric materials. Here, the authors present in-plane ferroelectricity in 2D Bi2TeO5 in which the ferroelectric domain size and shape can be continuously tuned by the Bi/Te ratio.
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5
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Yao J, Wang H, Yuan B, Hu Z, Wu C, Zhao A. Ultrathin Van der Waals Antiferromagnet CrTe 3 for Fabrication of In-Plane CrTe 3 /CrTe 2 Monolayer Magnetic Heterostructures. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2200236. [PMID: 35419894 DOI: 10.1002/adma.202200236] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 04/09/2022] [Indexed: 06/14/2023]
Abstract
Ultrathin van der Waals (vdW) magnets are heavily pursued for potential applications in developing high-density miniaturized electronic/spintronic devices as well as for topological physics in low-dimensional structures. Despite the rapid advances in ultrathin ferromagnetic vdW magnets, the antiferromagnetic counterparts, as well as the antiferromagnetic junctions, are much less studied owing to the difficulties in both material fabrication and magnetism characterization. Ultrathin CrTe3 layers have been theoretically proposed to be a vdW antiferromagnetic semiconductor with intrinsic intralayer antiferromagnetism. Herein, the epitaxial growth of monolayer (ML) and bilayer CrTe3 on graphite surface is demonstrated. The structure, electronic and magnetic properties of the ML CrTe3 are characterized by combining scanning tunneling microscopy/spectroscopy and non-contact atomic force microscopy and confirmed by density functional theory calculations. The CrTe3 MLs can be further utilized for the fabrication of a lateral heterojunction consisting of ML CrTe2 and ML CrTe3 with an atomically sharp and seamless interface. Since ML CrTe2 is a metallic vdW magnet, such a heterostructure presents the first in-plane magnetic metal-semiconductor heterojunction made of two vdW materials. The successful fabrication of ultrathin antiferromagnetic CrTe3 , as well as the magnetic heterojunction, will stimulate the development of miniaturized antiferromagnetic spintronic devices based on vdW materials.
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Affiliation(s)
- Jie Yao
- Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Han Wang
- School of Physics, Nankai University, Tianjin, 300071, China
| | - Bingkai Yuan
- School of Chemistry and Materials Science, CAS Center for Excellence in Nanoscience, and CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China, Hefei, 230026, China
| | - Zhenpeng Hu
- School of Physics, Nankai University, Tianjin, 300071, China
| | - Changzheng Wu
- School of Chemistry and Materials Science, CAS Center for Excellence in Nanoscience, and CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China, Hefei, 230026, China
| | - Aidi Zhao
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China
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6
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Haselmann U, Radlinger T, Pei W, Popov MN, Spitaler T, Romaner L, Ivanov YP, Chen J, He Y, Kothleitner G, Zhang Z. Ca Solubility in a BiFeO 3-Based System with a Secondary Bi 2O 3 Phase on a Nanoscale. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2022; 126:7696-7703. [PMID: 35558823 PMCID: PMC9082603 DOI: 10.1021/acs.jpcc.2c00674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 04/02/2022] [Indexed: 06/15/2023]
Abstract
In BiFeO3 (BFO), Bi2O3 (BO) is a known secondary phase, which can appear under certain growth conditions. However, BO is not just an unwanted parasitic phase but can be used to create the super-tetragonal BFO phase in films on substrates, which would otherwise grow in the regular rhombohedral phase (R-phase). The super-tetragonal BFO phase has the advantage of a much larger ferroelectric polarization of 130-150 μC/cm2, which is around 1.5 times the value of the rhombohedral phase with 80-100 μC/cm2. Here, we report that the solubility of Ca, which is a common dopant of bismuth ferrite materials to tune their properties, is significantly lower in the secondary BO phase than in the observed R-phase BFO. Starting from the film growth, this leads to completely different Ca concentrations in the two phases. We show this with advanced analytical transmission electron microscopy techniques and confirm the experimental results with density functional theory (DFT) calculations. At the film's fabrication temperature, caused by different solubilities, about 50 times higher Ca concentration is expected in the BFO phase than in the secondary one. Depending on the cooling rate after fabrication, this can further increase since a larger Ca concentration difference is expected at lower temperatures. When fabricating functional devices using Ca doping and the secondary BO phase, the difference in solubility must be considered because, depending on the ratio of the BO phase, the Ca concentration in the BFO phase can become much higher than intended. This can be critical for the intended device functionality because the Ca concentration strongly influences and modifies the BFO properties.
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Affiliation(s)
- Ulrich Haselmann
- Erich
Schmid Institute of Materials Science, Austrian Academy of Sciences, 8700 Leoben, Austria
| | - Thomas Radlinger
- Institute
for Electron Microscopy and Nanoanalysis, Graz University of Technology, 8010 Graz, Austria
| | - Weijie Pei
- School
of Materials Science & Engineering, Hubei University, 430062 Wuhan, Hubei, China
| | - Maxim N. Popov
- Materials
Center Leoben Forschung GmbH, 8700 Leoben, Austria
| | - Tobias Spitaler
- Department
of Materials Science, Montanuniversität
Leoben, 8700 Leoben, Austria
| | - Lorenz Romaner
- Materials
Center Leoben Forschung GmbH, 8700 Leoben, Austria
- Department
of Materials Science, Montanuniversität
Leoben, 8700 Leoben, Austria
| | - Yurii P. Ivanov
- Department
of Materials Science & Metallurgy, University
of Cambridge, Cambridge CB3 0FS, U.K.
- School
of Natural Sciences, Far Eastern Federal University, 690950 Vladivostok, Russia
| | - Jian Chen
- School
of Materials Science & Engineering, Hubei University, 430062 Wuhan, Hubei, China
| | - Yunbin He
- School
of Materials Science & Engineering, Hubei University, 430062 Wuhan, Hubei, China
| | - Gerald Kothleitner
- Institute
for Electron Microscopy and Nanoanalysis, Graz University of Technology, 8010 Graz, Austria
- Graz
Centre for Electron Microscopy, Austrian Cooperative Research, 8010 Graz, Austria
| | - Zaoli Zhang
- Erich
Schmid Institute of Materials Science, Austrian Academy of Sciences, 8700 Leoben, Austria
- Institute
of Material Physics, Montanuniversität Leoben, 8700 Leoben, Austria
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7
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Wei XK, Dunin-Borkowski RE, Mayer J. Structural Phase Transition and In-Situ Energy Storage Pathway in Nonpolar Materials: A Review. MATERIALS 2021; 14:ma14247854. [PMID: 34947446 PMCID: PMC8707040 DOI: 10.3390/ma14247854] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 12/09/2021] [Accepted: 12/16/2021] [Indexed: 11/27/2022]
Abstract
Benefitting from exceptional energy storage performance, dielectric-based capacitors are playing increasingly important roles in advanced electronics and high-power electrical systems. Nevertheless, a series of unresolved structural puzzles represent obstacles to further improving the energy storage performance. Compared with ferroelectrics and linear dielectrics, antiferroelectric materials have unique advantages in unlocking these puzzles due to the inherent coupling of structural transitions with the energy storage process. In this review, we summarize the most recent studies about in-situ structural phase transitions in PbZrO3-based and NaNbO3-based systems. In the context of the ultrahigh energy storage density of SrTiO3-based capacitors, we highlight the necessity of extending the concept of antiferroelectric-to-ferroelectric (AFE-to-FE) transition to broader antiferrodistortive-to-ferrodistortive (AFD-to-FD) transition for materials that are simultaneously ferroelastic. Combining discussion of the factors driving ferroelectricity, electric-field-driven metal-to-insulator transition in a (La1−xSrx)MnO3 electrode is emphasized to determine the role of ionic migration in improving the storage performance. We believe that this review, aiming at depicting a clearer structure–property relationship, will be of benefit for researchers who wish to carry out cutting-edge structure and energy storage exploration.
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Affiliation(s)
- Xian-Kui Wei
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Research Centre Jülich, 52425 Jülich, Germany; (R.E.D.-B.); (J.M.)
- Correspondence:
| | - Rafal E. Dunin-Borkowski
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Research Centre Jülich, 52425 Jülich, Germany; (R.E.D.-B.); (J.M.)
| | - Joachim Mayer
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Research Centre Jülich, 52425 Jülich, Germany; (R.E.D.-B.); (J.M.)
- Gemeinschaftslabor für Elektronenmikroskopie (GFE), RWTH Aachen University, 52074 Aachen, Germany
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8
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Haselmann U, Suyolcu YE, Wu PC, Ivanov YP, Knez D, van Aken PA, Chu YH, Zhang Z. Negatively Charged In-Plane and Out-Of-Plane Domain Walls with Oxygen-Vacancy Agglomerations in a Ca-Doped Bismuth-Ferrite Thin Film. ACS APPLIED ELECTRONIC MATERIALS 2021; 3:4498-4508. [PMID: 34723187 PMCID: PMC8552442 DOI: 10.1021/acsaelm.1c00638] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 09/12/2021] [Indexed: 06/13/2023]
Abstract
The interaction of oxygen vacancies and ferroelectric domain walls is of great scientific interest because it leads to different domain-structure behaviors. Here, we use high-resolution scanning transmission electron microscopy to study the ferroelectric domain structure and oxygen-vacancy ordering in a compressively strained Bi0.9Ca0.1FeO3-δ thin film. It was found that atomic plates, in which agglomerated oxygen vacancies are ordered, appear without any periodicity between the plates in out-of-plane and in-plane orientation. The oxygen non-stoichiometry with δ ≈ 1 in FeO2-δ planes is identical in both orientations and shows no preference. Within the plates, the oxygen vacancies form 1D channels in a pseudocubic [010] direction with a high number of vacancies that alternate with oxygen columns with few vacancies. These plates of oxygen vacancies always coincide with charged domain walls in a tail-to-tail configuration. Defects such as ordered oxygen vacancies are thereby known to lead to a pinning effect of the ferroelectric domain walls (causing application-critical aspects, such as fatigue mechanisms and countering of retention failure) and to have a critical influence on the domain-wall conductivity. Thus, intentional oxygen vacancy defect engineering could be useful for the design of multiferroic devices with advanced functionality.
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Affiliation(s)
- Ulrich Haselmann
- Erich
Schmid Institute of Materials Science, Austrian
Academy of Sciences, Leoben 8700, Austria
| | - Y. Eren Suyolcu
- Department
of Materials Science and Engineering, Cornell
University, Ithaca, New York 14850, United States
- Max
Planck Institute for Solid State Research, 70569 Stuttgart, Germany
| | - Ping-Chun Wu
- Department
of Materials Science and Engineering, National
Chiao Tung University, Hsinchu 30010, Taiwan
| | - Yurii P. Ivanov
- Erich
Schmid Institute of Materials Science, Austrian
Academy of Sciences, Leoben 8700, Austria
- Department
of Materials Science & Metallurgy, University
of Cambridge, Cambridge CB3 0FS, U.K.
- School of
Natural Sciences, Far Eastern Federal University, Vladivostok 690950, Russia
| | - Daniel Knez
- Graz
Centre for Electron Microscopy, Austrian
Cooperative Research, Graz 8010, Austria
| | - Peter A. van Aken
- Max
Planck Institute for Solid State Research, 70569 Stuttgart, Germany
| | - Ying-Hao Chu
- Department
of Materials Science and Engineering, National
Chiao Tung University, Hsinchu 30010, Taiwan
| | - Zaoli Zhang
- Erich
Schmid Institute of Materials Science, Austrian
Academy of Sciences, Leoben 8700, Austria
- Institute
of Material Physics, Montanuniversität
Leoben, Leoben 8700, Austria
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9
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Hu X, Hou X, Zhang Y, Chai X, Lian J, Wang C, Wang J, Jiang J, Jiang A. Size-Controlled Polarization Retention and Wall Current in Lithium Niobate Single-Crystal Memories. ACS APPLIED MATERIALS & INTERFACES 2021; 13:16641-16649. [PMID: 33793196 DOI: 10.1021/acsami.0c22969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Highly conductive domain walls in insulating ferroelectric LiNbO3 (LNO) single-crystal thin films with atomic smoothness are attractive for use in high-density integration of the ferroelectric domain wall random access memory (DWRAM) because of their excellent reliability and high read currents. However, downscaling of the memory size to the nanoscale could cause poor polarization retention. Understanding the size-dependent electrical performance of a memory cell is therefore crucial. In this work, highly insulating X-cut LNO thin films were bonded to SiO2/Si wafers and lateral mesa-like cells were fabricated on the film surfaces, where contact occurred with two-sided electrodes along the polar z-axis. Under application of an in-plane electric field above a coercive field (Ec), the domain within each memory cell was switched to be antiparallel to the unswitched referencing domain at the bottom; this resulted in the formation of a conducting domain wall, which enables the nondestructive readout strategy of the DWRAM. The cell, which has a lateral length (l) above a critical size (l0) of 105 nm, is found to be a mixture of two phases across the cell area. The inner area of the cell suffers from poor polarization retention because Ec = 150 kV/cm, as demonstrated by in-plane piezoresponse force microscopy imaging. In comparison, the outer periphery domains, which have lengths of 70 nm (∼l0/2), show good retention but require a much higher Ec of 785 kV/cm. The relevant physics is discussed as phase reconstruction occurs after release of the in-plane compressive strain near the outer regions; the results show good agreement with those of one-dimensional thermodynamic calculations and phase-field simulations. The measured current-voltage curves demonstrated a sudden enhancement of the wall current across the cell when l < l0, thus implying higher readout wall currents and better retention for the DWRAM at higher storage densities.
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Affiliation(s)
- Xiaobing Hu
- Stare Key Laboratory of ASIC & System, School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Xu Hou
- Department of Engineering Mechanics and Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Zhejiang University, Hangzhou 310027, China
| | - Yan Zhang
- Stare Key Laboratory of ASIC & System, School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Xiaojie Chai
- Stare Key Laboratory of ASIC & System, School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Jianwei Lian
- Stare Key Laboratory of ASIC & System, School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Chao Wang
- Stare Key Laboratory of ASIC & System, School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Jie Wang
- Department of Engineering Mechanics and Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Zhejiang University, Hangzhou 310027, China
| | - Jun Jiang
- Stare Key Laboratory of ASIC & System, School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Anquan Jiang
- Stare Key Laboratory of ASIC & System, School of Microelectronics, Fudan University, Shanghai 200433, China
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10
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Chen C, Wang C, Cai X, Xu C, Li C, Zhou J, Luo Z, Fan Z, Qin M, Zeng M, Lu X, Gao X, Kentsch U, Yang P, Zhou G, Wang N, Zhu Y, Zhou S, Chen D, Liu JM. Controllable defect driven symmetry change and domain structure evolution in BiFeO 3 with enhanced tetragonality. NANOSCALE 2019; 11:8110-8118. [PMID: 30984948 DOI: 10.1039/c9nr00932a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Defect engineering has been a powerful tool to enable the creation of exotic phases and the discovery of intriguing phenomena in ferroelectric oxides. However, the accurate control of the concentration of defects remains a big challenge. In this work, ion implantation, which can provide controllable point defects, allows us to produce a controlled defect driven true super-tetragonal (T) phase with a single-domain-state in ferroelectric BiFeO3 thin films. This point-defect engineering is found to drive the phase transition from the as-grown mixed rhombohedral-like (R) and tetragonal-like (MC) phase to true tetragonal (T) symmetry and induce the stripe multi-nanodomains to a single domain state. By further increasing the injected dose of the He ion, we demonstrate an enhanced tetragonality super-tetragonal (super-T) phase with the largest c/a ratio of ∼1.3 that has ever been experimentally achieved in BiFeO3. A combination of the morphology change and domain evolution further confirms that the mixed R/MC phase structure transforms to the single-domain-state true tetragonal phase. Moreover, the re-emergence of the R phase and in-plane nanoscale multi-domains after heat treatment reveal the memory effect and reversible phase transition and domain evolution. Our findings demonstrate the reversible control of R-Mc-T-super T symmetry changes (leading to the creation of true T phase BiFeO3 with enhanced tetragonality) and multidomain-single domain structure evolution through controllable defect engineering. This work also provides a pathway to generate large tetragonality (or c/a ratio) that could be extended to other ferroelectric material systems (such as PbTiO3, BaTiO3 and HfO2) which might lead to strong polarization enhancement.
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Affiliation(s)
- Chao Chen
- Institute for Advanced Materials, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China.
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11
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Li D, Zheng D, Jin C, Zheng W, Bai H. High-Performance Photovoltaic Readable Ferroelectric Nonvolatile Memory Based on La-Doped BiFeO 3 Films. ACS APPLIED MATERIALS & INTERFACES 2018; 10:19836-19843. [PMID: 29781272 DOI: 10.1021/acsami.8b06246] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Epitaxial La0.1Bi0.9FeO3 (LBFO) films with SrRuO3 (SRO) bottom electrodes were fabricated on SrTiO3(001) substrates by magnetron sputtering. The LBFO thin films exhibit strong ferroelectric properties. Nonvolatile reversible resistance switchings and switchable photovoltaic effects controlled by electric field have been observed in Pt/LBFO/SRO heterostructures. With the optimized LBFO film thickness, the observed room temperature pulsed-read resistance switching ratio can reach 105% magnitude by applying ±2.7 V pulse voltages. Besides, the observed ferroelectric switchable photovoltaic effect in the visible wavelength range shows a large tunable open-circuit photovoltage from -75 to -330 mV. The switching mechanisms in resistance and photovoltaic effects are demonstrated to be directly related to the ferroelectric reversal, which can be attributed to the polarization-modulated interfacial barriers and deep trap states.
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Affiliation(s)
- Dong Li
- Tianjin Key Laboratory of Low Dimensional Materials Physics and Processing Technology, Institute of Advanced Materials Physics, Faculty of Science , Tianjin University , Tianjin 300350 , People's Republic of China
| | - Dongxing Zheng
- Tianjin Key Laboratory of Low Dimensional Materials Physics and Processing Technology, Institute of Advanced Materials Physics, Faculty of Science , Tianjin University , Tianjin 300350 , People's Republic of China
| | - Chao Jin
- Tianjin Key Laboratory of Low Dimensional Materials Physics and Processing Technology, Institute of Advanced Materials Physics, Faculty of Science , Tianjin University , Tianjin 300350 , People's Republic of China
| | - Wanchao Zheng
- Tianjin Key Laboratory of Low Dimensional Materials Physics and Processing Technology, Institute of Advanced Materials Physics, Faculty of Science , Tianjin University , Tianjin 300350 , People's Republic of China
| | - Haili Bai
- Tianjin Key Laboratory of Low Dimensional Materials Physics and Processing Technology, Institute of Advanced Materials Physics, Faculty of Science , Tianjin University , Tianjin 300350 , People's Republic of China
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Dedon LR, Chen Z, Gao R, Qi Y, Arenholz E, Martin LW. Strain-Driven Nanoscale Phase Competition near the Antipolar-Nonpolar Phase Boundary in Bi 0.7La 0.3FeO 3 Thin Films. ACS APPLIED MATERIALS & INTERFACES 2018; 10:14914-14921. [PMID: 29637778 DOI: 10.1021/acsami.8b02597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Complex-oxide materials tuned to be near phase boundaries via chemistry/composition, temperature, pressure, etc. are known to exhibit large susceptibilities. Here, we observe a strain-driven nanoscale phase competition in epitaxially constrained Bi0.7La0.3FeO3 thin films near the antipolar-nonpolar phase boundary and explore the evolution of the structural, dielectric, (anti)ferroelectric, and magnetic properties with strain. We find that compressive and tensile strains can stabilize an antipolar PbZrO3-like Pbam phase and a nonpolar Pnma orthorhombic phase, respectively. Heterostructures grown with little to no strain exhibit a self-assembled nanoscale mixture of the two orthorhombic phases, wherein the relative fraction of each phase can be modified with film thickness. Subsequent investigation of the dielectric and (anti)ferroelectric properties reveals an electric-field-driven phase transformation from the nonpolar phase to the antipolar phase. X-ray linear dichroism reveals that the antiferromagnetic-spin axes can be effectively modified by the strain-induced phase transition. This evolution of antiferromagnetic-spin axes can be leveraged in exchange coupling between the antiferromagnetic Bi0.7La0.3FeO3 and a ferromagnetic Co0.9Fe0.1 layer to tune the ferromagnetic easy axis of the Co0.9Fe0.1. These results demonstrate that besides chemical alloying, epitaxial strain is an alternative and effective way to modify subtle phase relations and tune physical properties in rare earth-alloyed BiFeO3. Furthermore, the observation of antiferroelectric-antiferromagnetic properties in the Pbam Bi0.7La0.3FeO3 phase could be of significant scientific interest and great potential in magnetoelectric devices because of its dual antiferroic nature.
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Affiliation(s)
- Liv R Dedon
- Department of Materials Science and Engineering , University of California, Berkeley , Berkeley , California 94720 , United States
| | - Zuhuang Chen
- Department of Materials Science and Engineering , University of California, Berkeley , Berkeley , California 94720 , United States
- School of Materials Science and Engineering , Harbin Institute of Technology , Shenzhen 518055 , P. R. China
| | - Ran Gao
- Department of Materials Science and Engineering , University of California, Berkeley , Berkeley , California 94720 , United States
| | - Yajun Qi
- Department of Materials Science and Engineering , University of California, Berkeley , Berkeley , California 94720 , United States
- Department of Materials Science and Engineering , Hubei University , Wuhan 430062 , P. R. China
| | - Elke Arenholz
- Advanced Light Source , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Lane W Martin
- Department of Materials Science and Engineering , University of California, Berkeley , Berkeley , California 94720 , United States
- Materials Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
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Tian G, Chen D, Fan H, Li P, Fan Z, Qin M, Zeng M, Dai J, Gao X, Liu JM. Observation of Exotic Domain Structures in Ferroelectric Nanodot Arrays Fabricated via a Universal Nanopatterning Approach. ACS APPLIED MATERIALS & INTERFACES 2017; 9:37219-37226. [PMID: 28960060 DOI: 10.1021/acsami.7b12605] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We report a facile and cost-competitive nanopatterning route, using Ar ion beam etching through a monolayer polystyrene sphere (PS) array placed on a ferroelectric epitaxial thin film, to fabricate ordered ferroelectric nanodot arrays. Using this method, well-ordered BiFeO3 epitaxial nanodots, with tunable sizes from ∼100 to ∼900 nm in diameter, have been successfully synthesized. Interestingly, a plethora of exotic nanodomain structures, e.g., stripe domains, vortex and antivortex domains, and single domains, are observed in these nanodots. Moreover, this novel technique has been extended to produce Pb(Zr,Ti)O3 nanodots and multiferroic composite Co/BiFeO3 nanodots. These observations enable the creation of exotic domain structures and provide a wide range of application potentials for future nanoelectronic devices.
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Affiliation(s)
- Guo Tian
- Institute for Advanced Materials and Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, South China Academy of Advanced Optoelectronics, South China Normal University , Guangzhou 510006, China
| | - Deyang Chen
- Institute for Advanced Materials and Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, South China Academy of Advanced Optoelectronics, South China Normal University , Guangzhou 510006, China
| | - Hua Fan
- Institute for Advanced Materials and Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, South China Academy of Advanced Optoelectronics, South China Normal University , Guangzhou 510006, China
| | - Peilian Li
- Institute for Advanced Materials and Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, South China Academy of Advanced Optoelectronics, South China Normal University , Guangzhou 510006, China
| | - Zhen Fan
- Institute for Advanced Materials and Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, South China Academy of Advanced Optoelectronics, South China Normal University , Guangzhou 510006, China
| | - Minghui Qin
- Institute for Advanced Materials and Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, South China Academy of Advanced Optoelectronics, South China Normal University , Guangzhou 510006, China
| | - Min Zeng
- Institute for Advanced Materials and Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, South China Academy of Advanced Optoelectronics, South China Normal University , Guangzhou 510006, China
| | - Jiyan Dai
- Department of Applied Physics, Hong Kong Polytechnic University , Hong Kong, China
| | - Xingsen Gao
- Institute for Advanced Materials and Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, South China Academy of Advanced Optoelectronics, South China Normal University , Guangzhou 510006, China
| | - Jun-Ming Liu
- Institute for Advanced Materials and Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, South China Academy of Advanced Optoelectronics, South China Normal University , Guangzhou 510006, China
- Laboratory of Solid State Microstructures and Innovation Center of Advanced Microstructures, Nanjing University , Nanjing 210093, China
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Tian G, Chen D, Yao J, Luo Q, Fan Z, Zeng M, Zhang Z, Dai J, Gao X, Liu JM. BiFeO3 nanorings synthesized via AAO template-assisted pulsed laser deposition and ion beam etching. RSC Adv 2017. [DOI: 10.1039/c7ra07677k] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Well-ordered BiFeO3 nanorings with epitaxial structure, strong ferroelectricity and polarization reversal have been fabricated using this novel and facile method.
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