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Picavet E, De Geest K, Lievens E, Rijckaert H, Vandekerckhove T, Solano E, Deduytsche D, Van Bossele L, Van Thourhout D, De Buysser K, Beeckman J. Solution-Processed Pb(Zr,Ti)O 3 Thin Films with Strong Remnant Pockels Coefficient. ACS APPLIED MATERIALS & INTERFACES 2024. [PMID: 39077874 DOI: 10.1021/acsami.4c07073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/31/2024]
Abstract
In contrast to the widely studied electrical properties of Pb(Zr,Ti)O3 thin films, which have led to their applicability in various application areas such as thin film capacitors, microelectronics, and ferroelectric memories, the electro-optic (EO) properties are far less studied, which hinders the applicability of Pb(Zr,Ti)O3 films for EO applications such as heterogeneously integrated phase modulators in silicon (Si) photonics. Therefore, the EO properties of Pb(Zr,Ti)O3 films need to be further investigated to pave the way for the applicability of Pb(Zr,Ti)O3 films in EO applications. As the EO properties of ferroelectric thin films strongly depend on their crystal phase and texture, which in turn are influenced by the method of film fabrication. Therefore, in this work, we investigate the EO properties of a promising solution process using a La2O2CO3 template film. We successively characterize the precursor ink, microstructure and EO properties of the solution-processed Pb(Zr,Ti)O3film. The Pb(Zr,Ti)O3 film exhibits a fiber texture and has a large maximum and remnant Pockels coefficient (reff) of 69 pm V-1 and 66 pm V-1, respectively. The integration into a ring resonator-based modulator shows a VπL of 2.019 V cm. The determination of these promising EO properties could further pave the way for the applicability of Pb(Zr,Ti)O3 thin films in Si photonics.
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Affiliation(s)
- Ewout Picavet
- SCRiPTS, Department of Chemistry, Ghent University, Krijgslaan 281-S3, 9000 Ghent, Belgium
- LCP Group, Department of Electronics and Information Systems, Ghent University, Technologiepark - Zwijnaarde 126, 9052 Gent, Belgium
| | - Kobe De Geest
- LCP Group, Department of Electronics and Information Systems, Ghent University, Technologiepark - Zwijnaarde 126, 9052 Gent, Belgium
- PRG, Department of Information Technology, Ghent University-IMEC, Technologiepark - Zwijnaarde 126, 9052 Gent, Belgium
| | - Enes Lievens
- LCP Group, Department of Electronics and Information Systems, Ghent University, Technologiepark - Zwijnaarde 126, 9052 Gent, Belgium
- PRG, Department of Information Technology, Ghent University-IMEC, Technologiepark - Zwijnaarde 126, 9052 Gent, Belgium
| | - Hannes Rijckaert
- SCRiPTS, Department of Chemistry, Ghent University, Krijgslaan 281-S3, 9000 Ghent, Belgium
- LCP Group, Department of Electronics and Information Systems, Ghent University, Technologiepark - Zwijnaarde 126, 9052 Gent, Belgium
| | - Tom Vandekerckhove
- LCP Group, Department of Electronics and Information Systems, Ghent University, Technologiepark - Zwijnaarde 126, 9052 Gent, Belgium
| | - Eduardo Solano
- NCD-SWEET beamline, ALBA Synchrotron Light Source, Carrer de la Llum 2-26, 08290 Cerdanyola del Valles̀, Spain
| | - Davy Deduytsche
- CoCooN Group, Department of Solid State Sciences, Ghent University, Krijgslaan 281-S1, 9000 Ghent, Belgium
| | - Laura Van Bossele
- SCRiPTS, Department of Chemistry, Ghent University, Krijgslaan 281-S3, 9000 Ghent, Belgium
- LCP Group, Department of Electronics and Information Systems, Ghent University, Technologiepark - Zwijnaarde 126, 9052 Gent, Belgium
| | - Dries Van Thourhout
- PRG, Department of Information Technology, Ghent University-IMEC, Technologiepark - Zwijnaarde 126, 9052 Gent, Belgium
| | - Klaartje De Buysser
- SCRiPTS, Department of Chemistry, Ghent University, Krijgslaan 281-S3, 9000 Ghent, Belgium
| | - Jeroen Beeckman
- LCP Group, Department of Electronics and Information Systems, Ghent University, Technologiepark - Zwijnaarde 126, 9052 Gent, Belgium
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2
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You L, Abdelsamie A, Zhou Y, Chang L, Lim ZS, Wang J. Revisiting the Ferroelectric Photovoltaic Properties of Vertical BiFeO 3 Capacitors: A Comprehensive Study. ACS APPLIED MATERIALS & INTERFACES 2023; 15:12070-12077. [PMID: 36825749 DOI: 10.1021/acsami.2c23023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The ferroelectric photovoltaic effect has been extensively studied for possible applications in energy conversion and photo-electrics. The reversible spontaneous polarization gives rise to a switchable photovoltaic behavior. However, despite its long history, the origin of the ferroelectric photovoltaic effect still lacks a full understanding since multiple mechanisms such as bulk and Schottky-barrier-related interface effects are involved. Herein, we report a comprehensive study on the photovoltaic response of BiFeO3-based vertical heterostructures, using multiple strategies to clarify its origin. We found that, under white light illumination, polarization-modulated Schottky barrier at the interface is the dominating mechanism. By varying the top metal contacts, only the photovoltaic effect of the polarization downward state is strongly modulated, suggesting selective interface contribution in different polarization states. A Schottky-barrier-free device shows negligible photovoltaic effect, suggesting the lack of bulk photovoltaic effect in vertical heterostructures under white light illumination.
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Affiliation(s)
- Lu You
- Jiangsu Key Laboratory of Thin Films, School of Physical Science and Technology, Soochow University, 1 Shizi Street, Suzhou 215006, China
| | - Amr Abdelsamie
- School of Materials Science and Engineering, Nanyang Technological University, 639798 Singapore
| | - Yang Zhou
- Siyuan Laboratory, Guangzhou Key Laboratory of Vacuum Coating Technologies and New Energy Materials, Department of Physics, Jinan University, Guangzhou, Guangdong 510632, People's Republic of China
| | - Lei Chang
- School of Materials Science and Engineering, Nanyang Technological University, 639798 Singapore
| | - Zhi Shiuh Lim
- Physics Department, National University of Singapore, Block S12, #2 Science Drive 3, 117551 Singapore
| | - Junling Wang
- Department of Physics, Guangdong Provincial Key Laboratory of Functional Oxide Materials and Devices, Southern University of Science and Technology, Shenzhen 518055, Guangdong, China
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3
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Sando D. Strain and orientation engineering in ABO 3perovskite oxide thin films. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:153001. [PMID: 35042194 DOI: 10.1088/1361-648x/ac4c61] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 01/18/2022] [Indexed: 06/14/2023]
Abstract
Perovskite oxides with chemical formula ABO3are widely studied for their properties including ferroelectricity, magnetism, strongly correlated physics, optical effects, and superconductivity. A thriving research direction using such materials is through their integration as epitaxial thin films, allowing many novel and exotic effects to be discovered. The integration of the thin film on a single crystal substrate, however, can produce unique and powerful effects, and can even induce phases in the thin film that are not stable in bulk. The substrate imposed mechanical boundary conditions such as strain, crystallographic orientation, octahedral rotation patterns, and symmetry can also affect the functional properties of perovskite films. Here, the author reviews the current state of the art in epitaxial strain and orientation engineering in perovskite oxide thin films. The paper begins by introducing the effect of uniform conventional biaxial strain, and then moves to describe how the substrate crystallographic orientation can induce symmetry changes in the film materials. Various material case studies, including ferroelectrics, magnetically ordered materials, and nonlinear optical oxides are covered. The connectivity of the oxygen octahedra between film and substrate depending on the strain level as well as the crystallographic orientation is then discussed. The review concludes with open questions and suggestions worthy of the community's focus in the future.
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Affiliation(s)
- Daniel Sando
- School of Materials Science and Engineering, UNSW Sydney, Kensington, 2052, Australia
- ARC Centre of Excellence in Future Low Energy Electronics Technologies (FLEET), UNSW Sydney, Kensington, 2052, Australia
- Mark Wainwright Analytical Centre, UNSW Sydney, Kensington, 2052, Australia
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4
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Controlling polarization direction in epitaxial Pb(Zr 0.2Ti 0.8)O 3 films through Nb (n-type) and Fe (p-type) doping. Sci Rep 2022; 12:755. [PMID: 35031685 PMCID: PMC8760319 DOI: 10.1038/s41598-022-04802-1] [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: 09/09/2021] [Accepted: 12/24/2021] [Indexed: 11/12/2022] Open
Abstract
Fe (acceptor) and Nb (donor) doped epitaxial Pb(Zr0.2Ti0.8)O3 (PZT) films were grown on single crystal SrTiO3 substrates and their electric properties were compared to those of un-doped PZT layers deposited in similar conditions. All the films were grown from targets produced from high purity precursor oxides and the doping was in the limit of 1% atomic in both cases. The remnant polarization, the coercive field and the potential barriers at electrode interfaces are different, with lowest values for Fe doping and highest values for Nb doping, with un-doped PZT in between. The dielectric constant is larger in the doped films, while the effective density of charge carriers is of the same order of magnitude. An interesting result was obtained from piezoelectric force microscopy (PFM) investigations. It was found that the as-grown Nb-doped PZT has polarization orientated upward, while the Fe-doped PZT has polarization oriented mostly downward. This difference is explained by the change in the conduction type, thus in the sign of the carriers involved in the compensation of the depolarization field during the growth. In the Nb-doped film the majority carriers are electrons, which tend to accumulate to the growing surface, leaving positively charged ions at the interface with the bottom SrRuO3 electrode, thus favouring an upward orientation of polarization. For Fe-doped film the dominant carriers are holes, thus the sign of charges is opposite at the growing surface and the bottom electrode interface, favouring downward orientation of polarization. These findings open the way to obtain p-n ferroelectric homojunctions and suggest that PFM can be used to identify the type of conduction in PZT upon the dominant direction of polarization in the as-grown films.
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5
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Pradhan S, Rath M, David A, Kumar D, Prellier W, Rao MSR. Thickness-Dependent Domain Relaxation Dynamics Study in Epitaxial K 0.5Na 0.5NbO 3 Ferroelectric Thin Films. ACS APPLIED MATERIALS & INTERFACES 2021; 13:36407-36415. [PMID: 34309353 DOI: 10.1021/acsami.1c05699] [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
We explored the time dependence of the nanoscale domain relaxation mechanism in epitaxial K0.5Na0.5NbO3 (KNN) thin films grown on La0.67Sr0.33MnO3/SrTiO3 (001) substrates over the thickness range 20-80 nm using scanning probe microscopy. Kelvin probe force microscopy (KFM) and piezoresponse force microscopy were performed on pulsed-laser-deposition-deposited KNN thin films for studying the time evolution of trapped charges and polarized domains, respectively. The KFM data show that the magnitude and retention time of the surface potential are the maxima for 80 nm-thick film and reduce with the reduction in the film thickness. The charging and discharging of the samples reveal the easier and stronger electron trapping compared to hole trapping. This result further indicates the asymmetry between retention of the pulse-voltage-induced upward and downward domains. Furthermore, the time evolution of these ferroelectric nanodomains are found to obey stretched exponential behavior. The relaxation time (T) has been found to increase with increase in thickness; however, the corresponding stretched exponent (β) is reduced. Moreover, the written domain can retain for more than 2300 min in KNN thin films. An in-depth understanding of domain relaxation dynamics in Pb-free KNN thin films can bridge a path for future high-density memory applications.
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Affiliation(s)
- Soumen Pradhan
- Department of Physics, Materials Science Research Centre and Nano Functional Materials Technology Centre, Indian Institute of Technology Madras, Chennai 600 036, India
| | - Martando Rath
- Department of Physics, Materials Science Research Centre and Nano Functional Materials Technology Centre, Indian Institute of Technology Madras, Chennai 600 036, India
| | - Adrian David
- Laboratorie CRISMAT, CNRS UMR 6508, ENSICAEN, Normandie Universite, F-14050 Caen Cedex 4, France
| | - Deepak Kumar
- Laboratorie CRISMAT, CNRS UMR 6508, ENSICAEN, Normandie Universite, F-14050 Caen Cedex 4, France
| | - Wilfrid Prellier
- Laboratorie CRISMAT, CNRS UMR 6508, ENSICAEN, Normandie Universite, F-14050 Caen Cedex 4, France
| | - M S Ramachandra Rao
- Department of Physics, Materials Science Research Centre and Nano Functional Materials Technology Centre, Indian Institute of Technology Madras, Chennai 600 036, India
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6
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Yoon S, Gao X, Ok JM, Liao Z, Han MG, Zhu Y, Ganesh P, Chisholm MF, Choi WS, Lee HN. Strain-Induced Atomic-Scale Building Blocks for Ferromagnetism in Epitaxial LaCoO 3. NANO LETTERS 2021; 21:4006-4012. [PMID: 33929867 DOI: 10.1021/acs.nanolett.1c00756] [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
The origin of strain-induced ferromagnetism, which is robust regardless of the type and degree of strain in LaCoO3 (LCO) thin films, is enigmatic despite intensive research efforts over the past decade. Here, by combining scanning transmission electron microscopy with ab initio density functional theory plus U calculations, we report that the ferromagnetism does not emerge directly from the strain itself but rather from the creation of compressed structural units within ferroelastically formed twin-wall domains. The compressed structural units are magnetically active with the rocksalt-type high-spin/low-spin order. Our study highlights that the ferroelastic nature of ferromagnetic structural units is important for understanding the intriguing ferromagnetic properties in LCO thin films.
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Affiliation(s)
- Sangmoon Yoon
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Xiang Gao
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Jong Mok Ok
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Zhaoliang Liao
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Myung-Geun Han
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Yimei Zhu
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Panchapakesan Ganesh
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Matthew F Chisholm
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Woo Seok Choi
- Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Ho Nyung Lee
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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7
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Huang C, Liao Z, Li M, Guan C, Jin F, Ye M, Zeng X, Zhang T, Chen Z, Qi Y, Gao P, Chen L. A Highly Strained Phase in PbZr 0.2Ti 0.8O 3 Films with Enhanced Ferroelectric Properties. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:2003582. [PMID: 33898177 PMCID: PMC8061395 DOI: 10.1002/advs.202003582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 11/22/2020] [Indexed: 06/12/2023]
Abstract
Although epitaxial strain imparted by lattice mismatch between a film and the underlying substrate has led to distinct structures and emergent functionalities, the discrete lattice parameters of limited substrates, combined with strain relaxations driven by film thickness, result in severe obstructions to subtly regulate electro-elastic coupling properties in perovskite ferroelectric films. Here a practical and universal method to achieve highly strained phases with large tetragonal distortions in Pb-based ferroelectric films through synergetic effects of moderately (≈1.0%) misfit strains and laser fluences during pulsed laser deposition process is demonstrated. The phase possesses unexpectedly large Poisson's ratio and negative thermal expansion, and concomitant enhancements of spontaneous polarization (≈100 µC cm-2) and Curie temperature (≈800 °C), 40% and 75% larger than that of bulk counterparts, respectively. This strategy efficiently circumvents the long-standing issue of limited numbers of discrete substrates and enables continuous regulations of exploitable lattice states in functional oxide films with tightly elastic coupled performances beyond their present levels.
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Affiliation(s)
- Chuanwei Huang
- Shenzhen Key Laboratory of Special Functional MaterialsCollege of Materials Science and EngineeringShenzhen UniversityShenzhen518060China
| | - Zhaolong Liao
- Shenzhen Key Laboratory of Special Functional MaterialsCollege of Materials Science and EngineeringShenzhen UniversityShenzhen518060China
| | - Mingqiang Li
- Electron Microscopy Laboratory, and International Center for Quantum MaterialsSchool of PhysicsPeking UniversityBeijing100871China
| | - Changxin Guan
- Shenzhen Key Laboratory of Special Functional MaterialsCollege of Materials Science and EngineeringShenzhen UniversityShenzhen518060China
- Department of PhysicsSouthern University of Science and TechnologyShenzhenGuangdong518055China
- Department of Materials Science and EngineeringHubei UniversityWuhan430062China
| | - Fei Jin
- Shenzhen Key Laboratory of Special Functional MaterialsCollege of Materials Science and EngineeringShenzhen UniversityShenzhen518060China
| | - Mao Ye
- Department of PhysicsSouthern University of Science and TechnologyShenzhenGuangdong518055China
| | - Xierong Zeng
- Shenzhen Key Laboratory of Special Functional MaterialsCollege of Materials Science and EngineeringShenzhen UniversityShenzhen518060China
| | - Tianjin Zhang
- Department of Materials Science and EngineeringHubei UniversityWuhan430062China
| | - Zuhuang Chen
- School of Materials Science and EngineeringHarbin Institute of TechnologyShenzhen518055China
| | - Yajun Qi
- Department of Materials Science and EngineeringHubei UniversityWuhan430062China
| | - Peng Gao
- Electron Microscopy Laboratory, and International Center for Quantum MaterialsSchool of PhysicsPeking UniversityBeijing100871China
| | - Lang Chen
- Department of PhysicsSouthern University of Science and TechnologyShenzhenGuangdong518055China
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8
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Neumayer SM, Susner MA, McGuire MA, Pantelides ST, Kalnaus S, Maksymovych P, Balke N. Lowering of Tc in Van Der Waals Layered Materials Under In-Plane Strain. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2021; 68:253-258. [PMID: 32746203 DOI: 10.1109/tuffc.2020.3007290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The dependence of electromechanical behavior on strain in ferroelectric materials can be leveraged as parameter to tune ferroelectric properties such as the Curie temperature. For van der Waals materials, a unique opportunity arises because of wrinkling, bubbling, and Moiré phenomena accessible due to structural properties inherent to the van der Waals gap. Here, we use piezoresponse force microscopy and unsupervised machine learning methods to gain insight into the ferroelectric properties of layered CuInP2S6 where local areas are strained in-plane due to a partial delamination, resulting in a topographic bubble feature. We observe significant differences between strained and unstrained areas in piezoresponse images as well as voltage spectroscopy, during which strained areas show a sigmoid-shaped response usually associated with the response measured around the Curie temperature, indicating a lowering of the Curie temperature under tensile strain. These results suggest that strain engineering might be used to further increase the functionality of CuInP2S6 through locally modifying ferroelectric properties on the micro- and nanoscale.
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9
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Kwon O, Seol D, Qiao H, Kim Y. Recent Progress in the Nanoscale Evaluation of Piezoelectric and Ferroelectric Properties via Scanning Probe Microscopy. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:1901391. [PMID: 32995111 PMCID: PMC7507502 DOI: 10.1002/advs.201901391] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 06/05/2020] [Indexed: 05/21/2023]
Abstract
Piezoelectric and ferroelectric materials have garnered significant interest owing to their excellent physical properties and multiple potential applications. Accordingly, the need for evaluating piezoelectric and ferroelectric properties has also increased. The piezoelectric and ferroelectric properties are evaluated macroscopically using laser interferometers and polarization-electric field loop measurements. However, as the research focus is shifted from bulk to nanosized materials, scanning probe microscopy (SPM) techniques have been suggested as an alternative approach for evaluating piezoelectric and ferroelectric properties. In this Progress Report, the recent progress on the nanoscale evaluation of piezoelectric and ferroelectric properties of diverse materials using SPM-based methods is summarized. Among the SPM techniques, the focus is on recent studies that are related to piezoresponse force microscopy and conductive atomic force microscopy; further, the utilization of these two modes to understand piezoelectric and ferroelectric properties at the nanoscale level is discussed. This work can provide guidelines for evaluating the piezoelectric and ferroelectric properties of materials based on SPM techniques.
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Affiliation(s)
- Owoong Kwon
- School of Advanced Materials and Engineering & Research Center for Advanced Materials TechnologySungkyunkwan University (SKKU)Suwon16419Republic of Korea
| | - Daehee Seol
- School of Advanced Materials and Engineering & Research Center for Advanced Materials TechnologySungkyunkwan University (SKKU)Suwon16419Republic of Korea
| | - Huimin Qiao
- School of Advanced Materials and Engineering & Research Center for Advanced Materials TechnologySungkyunkwan University (SKKU)Suwon16419Republic of Korea
| | - Yunseok Kim
- School of Advanced Materials and Engineering & Research Center for Advanced Materials TechnologySungkyunkwan University (SKKU)Suwon16419Republic of Korea
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Lyu J, Song T, Fina I, Sánchez F. High polarization, endurance and retention in sub-5 nm Hf 0.5Zr 0.5O 2 films. NANOSCALE 2020; 12:11280-11287. [PMID: 32420576 DOI: 10.1039/d0nr02204g] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Ferroelectric HfO2 is a promising material for new memory devices, but significant improvement of its important properties is necessary for practical application. However, previous literature shows that a dilemma exists between polarization, endurance and retention. Since all these properties should be simultaneously high, overcoming this issue is of the highest relevance. Here, we demonstrate that high crystalline quality sub-5 nm Hf0.5Zr0.5O2 capacitors, integrated epitaxially with Si(001), present combined high polarization (2Pr of 27 μC cm-2 in the pristine state), endurance (2Pr > 6 μC cm-2 after 1011 cycles) and retention (2Pr > 12 μC cm-2 extrapolated at 10 years) using the same poling conditions (2.5 V). This achievement is demonstrated in films thinner than 5 nm, thus opening bright possibilities in ferroelectric tunnel junctions and other devices.
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Affiliation(s)
- Jike Lyu
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra 08193, Barcelona, Spain.
| | - Tingfeng Song
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra 08193, Barcelona, Spain.
| | - Ignasi Fina
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra 08193, Barcelona, Spain.
| | - Florencio Sánchez
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra 08193, Barcelona, Spain.
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Fang M, Wang Y, Wang H, Hou Y, Vetter E, Kou Y, Yang W, Yin L, Xiao Z, Li Z, Jiang L, Lee HN, Zhang S, Wu R, Xu X, Sun D, Shen J. Tuning the interfacial spin-orbit coupling with ferroelectricity. Nat Commun 2020; 11:2627. [PMID: 32457302 PMCID: PMC7250895 DOI: 10.1038/s41467-020-16401-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Accepted: 04/28/2020] [Indexed: 11/26/2022] Open
Abstract
Detection and manipulation of spin current lie in the core of spintronics. Here we report an active control of a net spin Hall angle, θSHE(net), in Pt at an interface with a ferroelectric material PZT (PbZr0.2Ti0.8O3), using its ferroelectric polarization. The spin Hall angle in the ultra-thin Pt layer is measured using the inverse spin Hall effect with a pulsed tunneling current from a ferromagnetic La0.67Sr0.33MnO3 electrode. The effect of the ferroelectric polarization on θSHE(net) is enhanced when the thickness of the Pt layer is reduced. When the Pt layer is thinner than 6 nm, switching the ferroelectric polarization even changes the sign of θSHE(net). This is attributed to the reversed polarity of the spin Hall angle in the 1st-layer Pt at the PZT/Pt interface when the ferroelectric polarization is inverted, as supported by the first-principles calculations. These findings suggest a route for designing future energy efficient spin-orbitronic devices using ferroelectric control. The spin Hall angle (SHA) is a measure of the efficiency for converting a charge to a spin current is still challenging to tune in situ. Here, the authors demonstrate by introducing a ferroelectric (FE) material in a ferromagnetic/heavy metal stack the SHA can be voltage controled via the polarization of the FE layer.
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Affiliation(s)
- Mei Fang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200433, Shanghai, China.,Hunan Key Laboratory of Super Microstructure and Ultrafast Process, School of Physics and Electronics, Central South University, 410083, Changsha, Hunan, China
| | - Yanmei Wang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200433, Shanghai, China
| | - Hui Wang
- Hunan Key Laboratory of Super Microstructure and Ultrafast Process, School of Physics and Electronics, Central South University, 410083, Changsha, Hunan, China.,Department of Physics and Astronomy, University of California, Irvine, CA, 92697, USA
| | - Yusheng Hou
- Department of Physics and Astronomy, University of California, Irvine, CA, 92697, USA
| | - Eric Vetter
- Department of Physics, North Carolina State University, Raleigh, NC, 27695, USA.,Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC, 27695, USA
| | - Yunfang Kou
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200433, Shanghai, China
| | - Wenting Yang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200433, Shanghai, China
| | - Lifeng Yin
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200433, Shanghai, China.,Institute for Nanoelectronics Devices and Quantum Computing, Fudan University, 200433, Shanghai, China.,Collaborative Innovation Center of Advanced Microstructures, 210093, Nanjing, China
| | - Zhu Xiao
- School of Materials Science and Engineering, Central South University, 410083, Changsha, Hunan, China
| | - Zhou Li
- School of Materials Science and Engineering, Central South University, 410083, Changsha, Hunan, China
| | - Lu Jiang
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Ho Nyung Lee
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Shufeng Zhang
- Department of Physics, University of Arizona, Tucson, AZ, 85721, USA
| | - Ruqian Wu
- Department of Physics and Astronomy, University of California, Irvine, CA, 92697, USA
| | - Xiaoshan Xu
- Department of Physics and Astronomy, Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE, 68588, USA.
| | - Dali Sun
- Department of Physics, North Carolina State University, Raleigh, NC, 27695, USA. .,Organic and Carbon Electronics Lab (ORaCEL), North Carolina State University, Raleigh, NC, 27695, USA.
| | - Jian Shen
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200433, Shanghai, China. .,Institute for Nanoelectronics Devices and Quantum Computing, Fudan University, 200433, Shanghai, China. .,Collaborative Innovation Center of Advanced Microstructures, 210093, Nanjing, China.
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12
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Ritz ET, Benedek NA. Interplay between Phonons and Anisotropic Elasticity Drives Negative Thermal Expansion in PbTiO_{3}. PHYSICAL REVIEW LETTERS 2018; 121:255901. [PMID: 30608816 DOI: 10.1103/physrevlett.121.255901] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Indexed: 06/09/2023]
Abstract
We use first-principles theory to show that the ingredients assumed to be essential to the occurrence of negative thermal expansion (NTE)-rigid unit phonon modes with negative Grüneisen parameters-are neither sufficient nor necessary for a material to undergo NTE. Instead, we find that NTE in PbTiO_{3} involves a delicate interplay between the phonon properties of a material (Grüneisen parameters) and its anisotropic elasticity. These unique insights open new avenues in our fundamental understanding of the thermal properties of materials and in the search for NTE in new materials classes.
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Affiliation(s)
- Ethan T Ritz
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, New York 14853, USA
| | - Nicole A Benedek
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA
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13
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Xu R, Gao R, Reyes-Lillo SE, Saremi S, Dong Y, Lu H, Chen Z, Lu X, Qi Y, Hsu SL, Damodaran AR, Zhou H, Neaton JB, Martin LW. Reducing Coercive-Field Scaling in Ferroelectric Thin Films via Orientation Control. ACS NANO 2018; 12:4736-4743. [PMID: 29641177 DOI: 10.1021/acsnano.8b01399] [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
The desire for low-power/voltage operation of devices is driving renewed interest in understanding scaling effects in ferroelectric thin films. As the dimensions of ferroelectrics are reduced, the properties can vary dramatically, including the robust scaling relationship between coercive field ( Ec) and thickness ( d), also referred to as the Janovec-Kay-Dunn (JKD) law, wherein Ec ∝ d-2/3. Here, we report that whereas (001)-oriented heterostructures follow JKD scaling across the thicknesses range of 20-330 nm, (111)-oriented heterostructures of the canonical tetragonal ferroelectric PbZr0.2Ti0.8O3 exhibit a deviation from JKD scaling wherein a smaller scaling exponent for the evolution of Ec is observed in films of thickness ≲ 165 nm. X-ray diffraction reveals that whereas (001)-oriented heterostructures remain tetragonal for all thicknesses, (111)-oriented heterostructures exhibit a transition from tetragonal-to-monoclinic symmetry in films of thickness ≲ 165 nm as a result of the compressive strain. First-principles calculations suggest that this symmetry change contributes to the deviation from the expected scaling, as the monoclinic phase has a lower energy barrier for switching. This structural evolution also gives rise to changes in the c/ a lattice parameter ratio, wherein this ratio increases and decreases in (001)- and (111)-oriented heterostructures, respectively, as the films are made thinner. In (111)-oriented heterostructures, this reduced tetragonality drives a reduction of the remanent polarization and, therefore, a reduction of the domain-wall energy and overall energy barrier to switching, which further exacerbates the deviation from the expected scaling. Overall, this work demonstrates a route toward reducing coercive fields in ferroelectric thin films and provides a possible mechanism to understand the deviation from JKD scaling.
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Affiliation(s)
- Ruijuan Xu
- Department of Materials Science and Engineering , University of California , Berkeley , California 94720 , United States
| | - Ran Gao
- Department of Materials Science and Engineering , University of California , Berkeley , California 94720 , United States
| | - Sebastian E Reyes-Lillo
- Departamento de Ciencias Físicas , Universidad Andres Bello , Santiago 837-0136 , Chile
- Department of Physics , University of California , Berkeley , California 94720 , United States
- Molecular Foundry , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Sahar Saremi
- Department of Materials Science and Engineering , University of California , Berkeley , California 94720 , United States
| | - Yongqi Dong
- National Synchrotron Radiation Laboratory and CAS Key Laboratory of Materials for Energy Conversion , University of Science and Technology of China , Hefei 230026 , China
| | - Hongling Lu
- Department of Materials Science and Engineering , University of California , Berkeley , California 94720 , United States
| | - Zuhuang Chen
- Department of Materials Science and Engineering , University of California , Berkeley , California 94720 , United States
| | - Xiaoyan Lu
- School of Civil Engineering , Harbin Institute of Technology , Harbin 150001 , China
| | - Yajun Qi
- Department of Materials Science and Engineering , Hubei University , Wuhan 430062 , China
| | - Shang-Lin Hsu
- Department of Materials Science and Engineering , University of California , Berkeley , California 94720 , United States
- Materials Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Anoop R Damodaran
- Department of Materials Science and Engineering , University of California , Berkeley , California 94720 , United States
| | - Hua Zhou
- X-ray Science Division, Advanced Photon Source , Argonne National Laboratory , Argonne , Illinois 60439 , United States
| | - Jeffrey B Neaton
- Department of Physics , University of California , Berkeley , California 94720 , United States
- Molecular Foundry , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
- Kavli Energy NanoScience Institute at Berkeley , Berkeley , California 94720 , United States
| | - Lane W Martin
- Department of Materials Science and Engineering , University of California , Berkeley , California 94720 , United States
- Materials Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
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14
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Watanabe Y. Calculation of strained BaTiO3 with different exchange correlation functionals examined with criterion by Ginzburg-Landau theory, uncovering expressions by crystallographic parameters. J Chem Phys 2018; 148:194702. [DOI: 10.1063/1.5022319] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Yukio Watanabe
- Department of Physics, Kyushu University, Fukuoka 819-0395, Japan
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15
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Kwon O, Seol D, Lee D, Han H, Lindfors-Vrejoiu I, Lee W, Jesse S, Lee HN, Kalinin SV, Alexe M, Kim Y. Direct Probing of Polarization Charge at Nanoscale Level. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:1703675. [PMID: 29134691 DOI: 10.1002/adma.201703675] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Revised: 09/25/2017] [Indexed: 06/07/2023]
Abstract
Ferroelectric materials possess spontaneous polarization that can be used for multiple applications. Owing to a long-term development of reducing the sizes of devices, the preparation of ferroelectric materials and devices is entering the nanometer-scale regime. Accordingly, to evaluate the ferroelectricity, there is a need to investigate the polarization charge at the nanoscale. Nonetheless, it is generally accepted that the detection of polarization charges using a conventional conductive atomic force microscopy (CAFM) without a top electrode is not feasible because the nanometer-scale radius of an atomic force microscopy (AFM) tip yields a very low signal-to-noise ratio. However, the detection is unrelated to the radius of an AFM tip and, in fact, a matter of the switched area. In this work, the direct probing of the polarization charge at the nanoscale is demonstrated using the positive-up-negative-down method based on the conventional CAFM approach without additional corrections or circuits to reduce the parasitic capacitance. The polarization charge densities of 73.7 and 119.0 µC cm-2 are successfully probed in ferroelectric nanocapacitors and thin films, respectively. The obtained results show the feasibility of the evaluation of polarization charge at the nanoscale and provide a new guideline for evaluating the ferroelectricity at the nanoscale.
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Affiliation(s)
- Owoong Kwon
- School of Advanced Materials and Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Daehee Seol
- School of Advanced Materials and Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Dongkyu Lee
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Hee Han
- Korea Research Institute of Standards and Science (KRISS), Daejeon, 34113, South Korea
| | | | - Woo Lee
- Korea Research Institute of Standards and Science (KRISS), Daejeon, 34113, South Korea
| | - Stephen Jesse
- The Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Ho Nyung Lee
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Sergei V Kalinin
- The Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Marin Alexe
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK
| | - Yunseok Kim
- School of Advanced Materials and Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
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16
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Herklotz A, Lee D, Guo EJ, Meyer TL, Petrie JR, Lee HN. Strain coupling of oxygen non-stoichiometry in perovskite thin films. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:493001. [PMID: 29130456 DOI: 10.1088/1361-648x/aa949b] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The effects of strain and oxygen vacancies on perovskite thin films have been studied in great detail over the past decades and have been treated separately from each other. While epitaxial strain has been realized as a tuning knob to tailor the functional properties of correlated oxides, oxygen vacancies are usually regarded as undesirable and detrimental. In transition metal oxides, oxygen defects strongly modify the properties and functionalities via changes in oxidation states of the transition metals. However, such coupling is not well understood in epitaxial films, but rather deemed as cumbersome or experimental artifact. Only recently it has been recognized that lattice strain and oxygen non-stoichiometry are strongly correlated in a vast number of perovskite systems and that this coupling can be beneficial for information and energy technologies. Recent experimental and theoretical studies have focused on understanding the correlated phenomena between strain and oxygen vacancies for a wide range of perovskite systems. These correlations not only include the direct relationship between elastic strain and the formation energy of oxygen vacancies, but also comprise highly complex interactions such as strain-induced phase transitions due to oxygen vacancy ordering. Therefore, we aim in this review to give a comprehensive overview on the coupling between strain and oxygen vacancies in perovskite oxides and point out the potential applications of the emergent functionalities strongly coupled to oxygen vacancies.
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Affiliation(s)
- Andreas Herklotz
- Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States of America
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17
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Herklotz A, Guo EJ, Wong AT, Meyer TL, Dai S, Ward TZ, Lee HN, Fitzsimmons MR. Reversible Control of Interfacial Magnetism through Ionic-Liquid-Assisted Polarization Switching. NANO LETTERS 2017; 17:1665-1669. [PMID: 28146633 DOI: 10.1021/acs.nanolett.6b04949] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The ability to control magnetism of materials via electric field enables a myriad of technological innovations in information storage, sensing, and computing. We use ionic-liquid-assisted ferroelectric switching to demonstrate reversible modulation of interfacial magnetism in a multiferroic heterostructure composed of ferromagnetic (FM) La0.8Sr0.2MnO3 and ferroelectric (FE) PbZr0.2Ti0.8O3. It is shown that ionic liquids can be used to persistently and reversibly switch a large area of a FE film. This is a prerequisite for polarized neutron reflectometry (PNR) studies that are conducted to directly probe magnetoelectric coupling of the FE polarization to the interfacial magnetization.
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Affiliation(s)
- Andreas Herklotz
- Materials Science and Technology Division, ‡Quantum Condensed Matter Division, and §Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Er-Jia Guo
- Materials Science and Technology Division, ‡Quantum Condensed Matter Division, and §Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Anthony T Wong
- Materials Science and Technology Division, ‡Quantum Condensed Matter Division, and §Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Tricia L Meyer
- Materials Science and Technology Division, ‡Quantum Condensed Matter Division, and §Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Sheng Dai
- Materials Science and Technology Division, ‡Quantum Condensed Matter Division, and §Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - T Zac Ward
- Materials Science and Technology Division, ‡Quantum Condensed Matter Division, and §Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Ho Nyung Lee
- Materials Science and Technology Division, ‡Quantum Condensed Matter Division, and §Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Michael R Fitzsimmons
- Materials Science and Technology Division, ‡Quantum Condensed Matter Division, and §Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
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18
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Laanait N, Zhang Z, Schlepütz CM. Imaging nanoscale lattice variations by machine learning of x-ray diffraction microscopy data. NANOTECHNOLOGY 2016; 27:374002. [PMID: 27505613 DOI: 10.1088/0957-4484/27/37/374002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We present a novel methodology based on machine learning to extract lattice variations in crystalline materials, at the nanoscale, from an x-ray Bragg diffraction-based imaging technique. By employing a full-field microscopy setup, we capture real space images of materials, with imaging contrast determined solely by the x-ray diffracted signal. The data sets that emanate from this imaging technique are a hybrid of real space information (image spatial support) and reciprocal lattice space information (image contrast), and are intrinsically multidimensional (5D). By a judicious application of established unsupervised machine learning techniques and multivariate analysis to this multidimensional data cube, we show how to extract features that can be ascribed physical interpretations in terms of common structural distortions, such as lattice tilts and dislocation arrays. We demonstrate this 'big data' approach to x-ray diffraction microscopy by identifying structural defects present in an epitaxial ferroelectric thin-film of lead zirconate titanate.
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Affiliation(s)
- Nouamane Laanait
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA. Institute for Functional Imaging of Materials, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
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19
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Seol D, Park S, Varenyk OV, Lee S, Lee HN, Morozovska AN, Kim Y. Determination of ferroelectric contributions to electromechanical response by frequency dependent piezoresponse force microscopy. Sci Rep 2016; 6:30579. [PMID: 27466086 PMCID: PMC4964340 DOI: 10.1038/srep30579] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 07/04/2016] [Indexed: 11/25/2022] Open
Abstract
Hysteresis loop analysis via piezoresponse force microscopy (PFM) is typically performed to probe the existence of ferroelectricity at the nanoscale. However, such an approach is rather complex in accurately determining the pure contribution of ferroelectricity to the PFM. Here, we suggest a facile method to discriminate the ferroelectric effect from the electromechanical (EM) response through the use of frequency dependent ac amplitude sweep with combination of hysteresis loops in PFM. Our combined study through experimental and theoretical approaches verifies that this method can be used as a new tool to differentiate the ferroelectric effect from the other factors that contribute to the EM response.
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Affiliation(s)
- Daehee Seol
- School of Advanced Materials Science and Engineering, Sungkyunkwan University (SKKU), Suwon, 440-746, Republic of Korea
| | - Seongjae Park
- School of Advanced Materials Science and Engineering, Sungkyunkwan University (SKKU), Suwon, 440-746, Republic of Korea
| | - Olexandr V Varenyk
- Institute of Physics, National Academy of Sciences of Ukraine, 46, pr. Nauki, 03028 Kyiv, Ukraine
| | - Shinbuhm Lee
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Ho Nyung Lee
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Anna N Morozovska
- Institute of Physics, National Academy of Sciences of Ukraine, 46, pr. Nauki, 03028 Kyiv, Ukraine
| | - Yunseok Kim
- School of Advanced Materials Science and Engineering, Sungkyunkwan University (SKKU), Suwon, 440-746, Republic of Korea
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20
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Damodaran AR, Agar JC, Pandya S, Chen Z, Dedon L, Xu R, Apgar B, Saremi S, Martin LW. New modalities of strain-control of ferroelectric thin films. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:263001. [PMID: 27187744 DOI: 10.1088/0953-8984/28/26/263001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Ferroelectrics, with their spontaneous switchable electric polarization and strong coupling between their electrical, mechanical, thermal, and optical responses, provide functionalities crucial for a diverse range of applications. Over the past decade, there has been significant progress in epitaxial strain engineering of oxide ferroelectric thin films to control and enhance the nature of ferroelectric order, alter ferroelectric susceptibilities, and to create new modes of response which can be harnessed for various applications. This review aims to cover some of the most important discoveries in strain engineering over the past decade and highlight some of the new and emerging approaches for strain control of ferroelectrics. We discuss how these new approaches to strain engineering provide promising routes to control and decouple ferroelectric susceptibilities and create new modes of response not possible in the confines of conventional strain engineering. To conclude, we will provide an overview and prospectus of these new and interesting modalities of strain engineering helping to accelerate their widespread development and implementation in future functional devices.
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Affiliation(s)
- Anoop R Damodaran
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, California, USA
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21
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Growth control of oxygen stoichiometry in homoepitaxial SrTiO3 films by pulsed laser epitaxy in high vacuum. Sci Rep 2016; 6:19941. [PMID: 26823119 PMCID: PMC4731809 DOI: 10.1038/srep19941] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Accepted: 12/15/2015] [Indexed: 11/10/2022] Open
Abstract
In many transition metal oxides, oxygen stoichiometry is one of the most critical parameters that plays a key role in determining the structural, physical, optical, and electrochemical properties of the material. However, controlling the growth to obtain high quality single crystal films having the right oxygen stoichiometry, especially in a high vacuum environment, has been viewed as a challenge. In this work, we show that, through proper control of the plume kinetic energy, stoichiometric crystalline films can be synthesized without generating oxygen defects even in high vacuum. We use a model homoepitaxial system of SrTiO3 (STO) thin films on single crystal STO substrates. Physical property measurements indicate that oxygen vacancy generation in high vacuum is strongly influenced by the energetics of the laser plume, and it can be controlled by proper laser beam delivery. Therefore, our finding not only provides essential insight into oxygen stoichiometry control in high vacuum for understanding the fundamental properties of STO-based thin films and heterostructures, but expands the utility of pulsed laser epitaxy of other materials as well.
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22
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Paskiewicz DM, Sichel-Tissot R, Karapetrova E, Stan L, Fong DD. Single-Crystalline SrRuO3 Nanomembranes: A Platform for Flexible Oxide Electronics. NANO LETTERS 2016; 16:534-42. [PMID: 26652204 DOI: 10.1021/acs.nanolett.5b04176] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The field of oxide electronics has benefited from the wide spectrum of functionalities available to the ABO3 perovskites, and researchers are now employing defect engineering in single crystalline heterostructures to tailor properties. However, bulk oxide single crystals are not conducive to many types of applications, particularly those requiring mechanical flexibility. Here, we demonstrate the realization of an all-oxide, single-crystalline nanomembrane heterostructure. With a surface-to-volume ratio of 2 × 10(7), the nanomembranes are fully flexible and can be readily transferred to other materials for handling purposes or for new materials integration schemes. Using in situ synchrotron X-ray scattering, we find that the nanomembranes can bond to other host substrates near room temperature and demonstrate coupling between surface reactivity and electromechanical properties in ferroelectric nanomembrane systems. The synthesis technique described here represents a significant advancement in materials integration and provides a new platform for the development of flexible oxide electronics.
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Affiliation(s)
- Deborah M Paskiewicz
- Materials Science Division, ‡Advanced Photon Source, and §Center for Nanoscale Materials, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Rebecca Sichel-Tissot
- Materials Science Division, ‡Advanced Photon Source, and §Center for Nanoscale Materials, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Evguenia Karapetrova
- Materials Science Division, ‡Advanced Photon Source, and §Center for Nanoscale Materials, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Liliana Stan
- Materials Science Division, ‡Advanced Photon Source, and §Center for Nanoscale Materials, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Dillon D Fong
- Materials Science Division, ‡Advanced Photon Source, and §Center for Nanoscale Materials, Argonne National Laboratory , Argonne, Illinois 60439, United States
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23
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Khan AI, Marti X, Serrao C, Ramesh R, Salahuddin S. Voltage-controlled ferroelastic switching in Pb(Zr0.2Ti0.8)O3 thin films. NANO LETTERS 2015; 15:2229-2234. [PMID: 25734797 DOI: 10.1021/nl503806p] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We report a voltage controlled reversible creation and annihilation of a-axis oriented ∼10 nm wide ferroelastic nanodomains without a concurrent ferroelectric 180° switching of the surrounding c-domain matrix in archetypal ferroelectric Pb(Zr0.2Ti0.8)O3 thin films by using the piezo-response force microscopy technique. In previous studies, the coupled nature of ferroelectric switching and ferroelastic rotation has made it difficult to differentiate the underlying physics of ferroelastic domain wall movement. Our observation of distinct thresholds for ferroelectric and ferroelastic switching allows us investigate the ferroelastic switching cleanly and demonstrate a new degree of nanoscale control over the ferroelastic domains.
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Affiliation(s)
| | - Xavier Marti
- ⊥Institute of Physics ASCR, v.v.i., Cukrovarnická 10, 162 53 Praha 6, Czech Republic
| | | | - Ramamoorthy Ramesh
- ∥Material Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Sayeef Salahuddin
- ∥Material Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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24
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Guo EJ, Roth R, Herklotz A, Hesse D, Dörr K. Ferroelectric 180° domain wall motion controlled by biaxial strain. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2015; 27:1615-1618. [PMID: 25594771 DOI: 10.1002/adma.201405205] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 12/15/2014] [Indexed: 06/04/2023]
Abstract
180° domain wall motion in a tetragonal ferroelectric oxide is accelerated by an order of magnitude using in situ strain in a force microscope. Single-domain PbZr0.2 Ti0.8 O3 films on piezoelectric (001)-oriented 0.72PbMg1/3 Nb2/3 O3 -0.28PbTiO3 substrates allow for direct investigation of strain-dependent domain dynamics. The strain effect depends on the sign of applied field through strain-dependent electrode built-in potentials and a suggested charging of tilted walls.
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Affiliation(s)
- Er-Jia Guo
- Institute for Physics, Martin-Luther-University, Halle-Wittenberg, 06099, Halle, Germany; Institute for Metallic Materials, IFW Dresden, Postfach 270116, 01069, Dresden, Germany
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25
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Sun D, Fang M, Xu X, Jiang L, Guo H, Wang Y, Yang W, Yin L, Snijders PC, Ward TZ, Gai Z, Zhang XG, Lee HN, Shen J. Active control of magnetoresistance of organic spin valves using ferroelectricity. Nat Commun 2014; 5:4396. [PMID: 25008155 PMCID: PMC4104453 DOI: 10.1038/ncomms5396] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Accepted: 06/13/2014] [Indexed: 11/23/2022] Open
Abstract
Organic spintronic devices have been appealing because of the long spin lifetime of the charge carriers in the organic materials and their low cost, flexibility and chemical diversity. In previous studies, the control of resistance of organic spin valves is generally achieved by the alignment of the magnetization directions of the two ferromagnetic electrodes, generating magnetoresistance. Here we employ a new knob to tune the resistance of organic spin valves by adding a thin ferroelectric interfacial layer between the ferromagnetic electrode and the organic spacer: the magnetoresistance of the spin valve depends strongly on the history of the bias voltage, which is correlated with the polarization of the ferroelectric layer; the magnetoresistance even changes sign when the electric polarization of the ferroelectric layer is reversed. These findings enable active control of resistance using both electric and magnetic fields, opening up possibility for multi-state organic spin valves.
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Affiliation(s)
- Dali Sun
- State Key Laboratory of Surface Physics and Department of Physics and Collaborative Innovation Center of Advanced Microstructure, Fudan University, Shanghai 200433, China
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
- These authors contributed equally to this work
- Present address: Department of Physics and Astronomy, University of Utah, Salt Lake City, Utah 84112, USA
| | - Mei Fang
- State Key Laboratory of Surface Physics and Department of Physics and Collaborative Innovation Center of Advanced Microstructure, Fudan University, Shanghai 200433, China
- These authors contributed equally to this work
| | - Xiaoshan Xu
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Lu Jiang
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Hangwen Guo
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Yanmei Wang
- State Key Laboratory of Surface Physics and Department of Physics and Collaborative Innovation Center of Advanced Microstructure, Fudan University, Shanghai 200433, China
| | - Wenting Yang
- State Key Laboratory of Surface Physics and Department of Physics and Collaborative Innovation Center of Advanced Microstructure, Fudan University, Shanghai 200433, China
| | - Lifeng Yin
- State Key Laboratory of Surface Physics and Department of Physics and Collaborative Innovation Center of Advanced Microstructure, Fudan University, Shanghai 200433, China
| | - Paul C. Snijders
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - T. Z. Ward
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Zheng Gai
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - X.-G. Zhang
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Ho Nyung Lee
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Jian Shen
- State Key Laboratory of Surface Physics and Department of Physics and Collaborative Innovation Center of Advanced Microstructure, Fudan University, Shanghai 200433, China
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
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Jiang L, Choi WS, Jeen H, Dong S, Kim Y, Han MG, Zhu Y, Kalinin SV, Dagotto E, Egami T, Lee HN. Tunneling electroresistance induced by interfacial phase transitions in ultrathin oxide heterostructures. NANO LETTERS 2013; 13:5837-5843. [PMID: 24205817 DOI: 10.1021/nl4025598] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The ferroelectric (FE) control of electronic transport is one of the emerging technologies in oxide heterostructures. Many previous studies in FE tunnel junctions (FTJs) exploited solely the differences in the electrostatic potential across the FTJs that are induced by changes in the FE polarization direction. Here, we show that in practice the junction current ratios between the two polarization states can be further enhanced by the electrostatic modification in the correlated electron oxide electrodes, and that FTJs with nanometer thin layers can effectively produce a considerably large electroresistance ratio at room temperature. To understand these surprising results, we employed an additional control parameter, which is related to the crossing of electronic and magnetic phase boundaries of the correlated electron oxide. The FE-induced phase modulation at the heterointerface ultimately results in an enhanced electroresistance effect. Our study highlights that the strong coupling between degrees of freedom across heterointerfaces could yield versatile and novel applications in oxide electronics.
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Affiliation(s)
- Lu Jiang
- Materials Science and Technology Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
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27
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Choi WS, Rouleau CM, Seo SSA, Luo Z, Zhou H, Fister TT, Eastman JA, Fuoss PH, Fong DD, Tischler JZ, Eres G, Chisholm MF, Lee HN. Atomic layer engineering of perovskite oxides for chemically sharp heterointerfaces. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2012; 24:6423-6428. [PMID: 23034879 DOI: 10.1002/adma.201202691] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 08/03/2012] [Indexed: 06/01/2023]
Abstract
Atomic layer engineering enables fabrication of a chemically sharp oxide heterointerface. The interface formation and strain evolution during the initial growth of LaAlO(3) /SrTiO(3) heterostructures by pulsed laser deposition are investigated in search of a means for controlling the atomic-sharpness of the interface. This study shows that inserting a monolayer of LaAlO(3) grown at high oxygen pressure dramatically enhances interface abruptness.
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Affiliation(s)
- Woo Seok Choi
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
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28
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Lee D, Jeon BC, Baek SH, Yang SM, Shin YJ, Kim TH, Kim YS, Yoon JG, Eom CB, Noh TW. Active control of ferroelectric switching using defect-dipole engineering. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2012; 24:6490-6495. [PMID: 23023876 DOI: 10.1002/adma.201203101] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Revised: 09/05/2012] [Indexed: 06/01/2023]
Abstract
Active control of defect structures and associated polarization switching in a ferroelectric material is achieved without compromising its ferroelectric properties. Based on dipolar interaction between defect dipole and polarization, the unique functionality of the defect dipole to control ferroelectric switching is visualized. This approach can provide a foundation for novel ferroelectric applications, such as high-density multilevel data storage.
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Affiliation(s)
- Daesu Lee
- IBS-Center for Functional Interfaces of Correlated Electron Systems and Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea
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29
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Lee D, Yang SM, Kim TH, Jeon BC, Kim YS, Yoon JG, Lee HN, Baek SH, Eom CB, Noh TW. Multilevel data storage memory using deterministic polarization control. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2012; 24:402-406. [PMID: 22162010 DOI: 10.1002/adma.201103679] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Revised: 11/04/2011] [Indexed: 05/31/2023]
Abstract
Multilevel non-volatile memory for high-density date storage is achieved by using the deterministic control of ferroelectric polarization. In a real ferroelectric thin-film system, eight stable and reproducible polarization states are realized (i.e., 3-bit data storage) by adjusting the displacement current. This approach can be used to triple or quadruple the memory density, even at existing feature scales.
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Affiliation(s)
- Daesu Lee
- ReCFI, Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea
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30
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Kim DH, Kim YK, Hong S, Kim Y, Baik S. Nanoscale bit formation in highly (111)-oriented ferroelectric thin films deposited on glass substrates for high-density storage media. NANOTECHNOLOGY 2011; 22:245705. [PMID: 21508503 DOI: 10.1088/0957-4484/22/24/245705] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
PbTiO(3) (PTO) ferroelectric films on Pt(111) bottom electrode layers covering Ta/glass were prepared using pulsed laser deposition. X-ray diffraction patterns revealed that the PTO films were preferentially (111)-oriented. The films were highly crystalline and had a smooth surface with root mean square (RMS) roughness of 1.5 nm. Ferroelectric properties of the PTO films were characterized using piezoresponse force microscopy (PFM). PFM techniques achieved ferroelectric polarization bits with a minimum width of 22 nm, which corresponds to a potential recording density of 1.3 Tbit/in(2) in ferroelectric storage devices.
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Affiliation(s)
- Dae Hong Kim
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Korea
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31
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Ko H, Ryu K, Park H, Park C, Jeon D, Kim YK, Jung J, Min DK, Kim Y, Lee HN, Park Y, Shin H, Hong S. High-resolution field effect sensing of ferroelectric charges. NANO LETTERS 2011; 11:1428-1433. [PMID: 21375284 DOI: 10.1021/nl103372a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Nanoscale manipulation of surface charges and their imaging are essential for understanding local electronic behaviors of polar materials and advanced electronic devices. Electrostatic force microscopy and Kelvin probe force microscopy have been extensively used to probe and image local surface charges responsible for electrodynamics and transport phenomena. However, they rely on the weak electric force modulation of cantilever that limits both spatial and temporal resolutions. Here we present a field effect transistor embedded probe that can directly image surface charges on a length scale of 25 nm and a time scale of less than 125 μs. On the basis of the calculation of net surface charges in a 25 nm diameter ferroelectric domain, we could estimate the charge density resolution to be as low as 0.08 μC/cm(2), which is equivalent to 1/20 electron per nanometer square at room temperature.
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Affiliation(s)
- Hyoungsoo Ko
- Semiconductor Device Laboratory, Samsung Advanced Institute of Technology, Yongin 446-712, Korea
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32
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Chisholm MF, Luo W, Oxley MP, Pantelides ST, Lee HN. Atomic-scale compensation phenomena at polar interfaces. PHYSICAL REVIEW LETTERS 2010; 105:197602. [PMID: 21231196 DOI: 10.1103/physrevlett.105.197602] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Indexed: 05/30/2023]
Abstract
The interfacial screening charge that arises to compensate electric fields of dielectric or ferroelectric thin films is now recognized as the most important factor in determining the capacitance or polarization of ultrathin ferroelectrics. Here we investigate using aberration-corrected electron microscopy and density-functional theory to show how interfaces cope with the need to terminate ferroelectric polarization. In one case, we show evidence for ionic screening, which has been predicted by theory but never observed. For a ferroelectric film on an insulating substrate, we found that compensation can be mediated by an interfacial charge generated, for example, by oxygen vacancies.
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Affiliation(s)
- Matthew F Chisholm
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
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33
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Infante IC, Lisenkov S, Dupé B, Bibes M, Fusil S, Jacquet E, Geneste G, Petit S, Courtial A, Juraszek J, Bellaiche L, Barthélémy A, Dkhil B. Bridging multiferroic phase transitions by epitaxial strain in BiFeO3. PHYSICAL REVIEW LETTERS 2010; 105:057601. [PMID: 20867953 DOI: 10.1103/physrevlett.105.057601] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Indexed: 05/05/2023]
Abstract
We report the influence of epitaxial strain on the multiferroic phase transitions of BiFeO3 films. Using advanced characterization techniques and calculations we show that while the magnetic Néel temperature hardly varies, the ferroelectric Curie temperature TC decreases dramatically with strain. This is in contrast with the behavior of standard ferroelectrics where strain enhances the polar cation shifts and thus TC. We argue that this is caused by an interplay of polar and oxygen tilting instabilities and that strain can drive both transitions close together to yield increased magnetoelectric responses.
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Affiliation(s)
- I C Infante
- Unité Mixte de Physique CNRS/Thales, 1 avenue Fresnel, Campus de l'Ecole Polytechnique, 91767 Palaiseau, France
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34
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Bin-Omran S. The influence of strain on the polarization of epitaxial (Ba(0.70)Sr(0.30))TiO(3) ultrathin film obtained from first principles. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:275901. [PMID: 21399266 DOI: 10.1088/0953-8984/22/27/275901] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A first-principles-derived approach is used to investigate the temperature-versus-misfit strain phase diagram of (Ba(0.70)Sr(0.30))TiO(3) ultrathin film. Our predicted phase diagram is qualitatively similar to those developed by Shirokov et al (2009 Phys. Rev. B 79 144118) and Ban and Alpay (2002 J. Appl. Phys. 91 9288). However, there are some quantitative differences that are microscopically revealed and explained. The results also indicate that the electrical polarization is very sensitive to the applied strain. Moreover, the polarization components show a strong dependence on the surface/interface, thickness, and electrical boundary conditions.
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Affiliation(s)
- S Bin-Omran
- Department of Physics and Astronomy, King Saud University, PO Box 2455, Riyadh 11451, Saudi Arabia.
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35
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Kukhar VG, Pertsev NA, Kholkin AL. Thermodynamic theory of strain-mediated direct magnetoelectric effect in multiferroic film-substrate hybrids. NANOTECHNOLOGY 2010; 21:265701. [PMID: 20522925 DOI: 10.1088/0957-4484/21/26/265701] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A nonlinear thermodynamic theory is developed for the strain-mediated direct magnetoelectric (ME) effect displayed by ferroelectric-ferromagnetic nanostructures. This effect results from transmission of magnetic-field-induced deformations of a thick ferromagnetic substrate to a thin ferroelectric overlayer, where the polarization changes due to lattice strains. The strain-dependent polarization and permittivity of an epitaxial nanolayer (few tens of nm thick) are calculated using the thermodynamic theory of single-domain ferroelectric films. The substrate magnetostrictive deformations are described phenomenologically, taking into account their nonlinear variation with magnetic field. The calculations show that ME polarization and voltage coefficients strongly depend on the initial strain state of the film. For BaTiO(3) and PbTiO(3) films deposited on Co(0.8)Zn(0.2)Fe(2)O(4), the out-of-plane polarization and related ME coefficients are calculated numerically as a function of magnetic field parallel to the interface. For films stabilized in the monoclinic phase, this transverse ME response depends on the orientation of magnetic field relative to their in-plane crystallographic axes. The longitudinal ME coefficient is also evaluated and, for a substrate geometry minimizing the demagnetizing field, predicted to be comparable to the transverse one. For BaTiO(3) and PbTiO(3) films deposited on Terfenol-D, the calculations yield high ME polarization coefficients approximately 10(-7) s m(-1) and giant ME voltage coefficients approximately 50 V cm(-1) Oe(-1).
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Affiliation(s)
- V G Kukhar
- Visual Trading Systems LLC, St Petersburg Branch, 194044 St Petersburg, Russia
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36
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Jo JY, Yang SM, Kim TH, Lee HN, Yoon JG, Park S, Jo Y, Jung MH, Noh TW. Nonlinear dynamics of domain-wall propagation in epitaxial ferroelectric thin films. PHYSICAL REVIEW LETTERS 2009; 102:045701. [PMID: 19257442 DOI: 10.1103/physrevlett.102.045701] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2008] [Revised: 11/28/2008] [Indexed: 05/27/2023]
Abstract
We investigated the ferroelectric domain-wall propagation in epitaxial Pb(Zr,Ti)O3 thin film over a wide temperature range (3-300 K). We measured the domain-wall velocity under various electric fields and found that the velocity data is strongly nonlinear with electric fields, especially at low temperature. We found that, as one of surface growth issues, our domain-wall velocity data from ferroelectric epitaxial film could be classified into the creep, depinning, and flow regimes due to competition between disorder and elasticity. The measured values of velocity and dynamical exponents indicate that the ferroelectric domain walls in the epitaxial films are fractal and pinned by a disorder-induced local field.
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Affiliation(s)
- J Y Jo
- Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea
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37
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Christen HM, Eres G. Recent advances in pulsed-laser deposition of complex oxides. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2008; 20:264005. [PMID: 21694339 DOI: 10.1088/0953-8984/20/26/264005] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Pulsed-laser deposition (PLD) is one of the most promising techniques for the formation of complex-oxide heterostructures, superlattices, and well controlled interfaces. The first part of this paper presents a review of several useful modifications of the process, including methods inspired by combinatorial approaches. We then discuss detailed growth kinetics results, which illustrate that 'true' layer-by-layer (LBL) growth can only be approached, not fully met, even though many characterization techniques reveal interfaces with unexpected sharpness. Time-resolved surface x-ray diffraction measurements show that crystallization and the majority of interlayer mass transport occur on timescales that are comparable to those of the plume/substrate interaction, providing direct experimental evidence that a growth regime exists in which non-thermal processes dominate PLD. This understanding shows how kinetic growth manipulation can bring PLD closer to ideal LBL than any other growth method available today.
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Affiliation(s)
- H M Christen
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
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38
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Dawber M, Stucki N, Lichtensteiger C, Gariglio S, Triscone JM. New phenomena at the interfaces of very thin ferroelectric oxides. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2008; 20:264015. [PMID: 21694349 DOI: 10.1088/0953-8984/20/26/264015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We present a brief review of the role of interfacial physics in ferroelectric oxides, with an emphasis on the importance of boundary conditions that determine the properties of very thin ferroelectric films and superlattices. As well as discussing the screening problem, and the role of strain and electrostatics in ferroelectrics, we highlight some of the possibilities in fine period superlattices where the high density of interfaces can lead to new and potentially useful phenomena.
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Affiliation(s)
- M Dawber
- DPMC, University of Geneva, 24 Quai Ernest Ansermet, 1211 Geneva 4, Switzerland. Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800, USA
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39
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Frantti J. Notes of the recent structural studies on lead zirconate titanate. J Phys Chem B 2008; 112:6521-35. [PMID: 18433161 DOI: 10.1021/jp711829t] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Atomic scale structure has a central importance for the understanding of functional properties of ferroelectrics. The X-ray and neutron diffraction studies used for the average symmetry determination of lead zirconate titanate [Pb(ZrxTi(1- x))O3, PZT] ceramics and powders are reviewed. The results obtained through two frequently used local probes, transmission electron microscopy (TEM) combined with electron diffraction (ED) and Raman scattering measurements, are summarized. On the basis of these studies, structural trends as a function of composition x and temperature are outlined. There are two distinguished intrinsic structural features, (i) lead-ion shifts and (ii) local structural distortions related to different B cations and the spatial composition variation of x, which have a pronounced effect on the functional properties of PZT. Particular attention is paid to the morphotropic phase boundary (MPB) compositions for which a large number of different structural models have been proposed. Earlier symmetry considerations show that the monoclinic phase cannot serve as a continuous bridge between tetragonal and rhombohedral phases. This suggests that the two-phase coexistence has an important role for the piezoelectric properties. Near the MPB, the extrinsic contribution to piezoelectricity includes pressure (or electric-field)-induced changes in phase fractions and domain wall motion. It was recently shown that the domain contribution is crucial for the electromechanical properties of PZT in the vicinity of the MPB. The dependence of domain widths on crystal size and shape should also be properly accounted for when TEM/ED measurements complement X-ray and/or neutron diffraction experiments. The structure-piezoelectric property relations are summarized.
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Affiliation(s)
- J Frantti
- Laboratory of Physics, Helsinki University of Technology, P.O. Box 4100, FIN-02015 HUT, Finland.
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40
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Grigoriev A, Sichel R, Lee HN, Landahl EC, Adams B, Dufresne EM, Evans PG. Nonlinear piezoelectricity in epitaxial ferroelectrics at high electric fields. PHYSICAL REVIEW LETTERS 2008; 100:027604. [PMID: 18232927 DOI: 10.1103/physrevlett.100.027604] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2007] [Indexed: 05/25/2023]
Abstract
Nonlinear effects in the coupling of polarization with elastic strain have been predicted to occur in ferroelectric materials subjected to high electric fields. Such predictions are tested here for a PbZr0.2Ti0.8O3 ferroelectric thin film at electric fields in the range of several hundred MV/m and strains reaching up to 2.7%. The piezoelectric strain exceeds predictions based on constant piezoelectric coefficients at electric fields from approximately 200 to 400 MV/m, which is consistent with a nonlinear effect predicted to occur at corresponding piezoelectric distortions.
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Affiliation(s)
- Alexei Grigoriev
- Department of Materials Science and Engineering, University of Wisconsin, Madison, Wisconsin 53706, USA
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