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Ganguly S, Pesquera D, Garcia DM, Saeed U, Mirzamohammadi N, Santiso J, Padilla J, Roque JMC, Laulhé C, Berenguer F, Villanueva LG, Catalan G. Photostrictive Actuators Based on Freestanding Ferroelectric Membranes. Adv Mater 2024:e2310198. [PMID: 38546029 DOI: 10.1002/adma.202310198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 03/12/2024] [Indexed: 04/26/2024]
Abstract
Complex oxides offer a wide range of functional properties, and recent advances in the fabrication of freestanding membranes of these oxides are adding new mechanical degrees of freedom to this already rich functional ecosystem. Here, photoactuation is demonstrated in freestanding thin film resonators of ferroelectric Barium Titanate (BaTiO3) and paraelectric Strontium Titanate (SrTiO3). The free-standing films, transferred onto perforated supports, act as nano-drums, oscillating at their natural resonance frequency when illuminated by a frequency-modulated laser. The light-induced deflections in the ferroelectric BaTiO3 membranes are two orders of magnitude larger than in the paraelectric SrTiO3 ones. Time-resolved X-ray micro-diffraction under illumination and temperature-dependent holographic interferometry provide combined evidence for the photostrictive strain in BaTiO3 originating from a partial screening of ferroelectric polarization by photo-excited carriers, which decreases the tetragonality of the unit cell. These findings showcase the potential of photostrictive freestanding ferroelectric films as wireless actuators operated by light.
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Affiliation(s)
- Saptam Ganguly
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, Barcelona, 08193, Catalonia, Spain
| | - David Pesquera
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, Barcelona, 08193, Catalonia, Spain
| | - Daniel Moreno Garcia
- Advanced NEMS Laboratory, Institute of Mechanical Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, 1015, Switzerland
| | - Umair Saeed
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, Barcelona, 08193, Catalonia, Spain
| | - Nona Mirzamohammadi
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, Barcelona, 08193, Catalonia, Spain
| | - José Santiso
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, Barcelona, 08193, Catalonia, Spain
| | - Jessica Padilla
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, Barcelona, 08193, Catalonia, Spain
| | - José Manuel Caicedo Roque
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, Barcelona, 08193, Catalonia, Spain
| | - Claire Laulhé
- Université Paris-Saclay, Synchrotron SOLEIL, Saint-Aubin, 91190, France
| | - Felisa Berenguer
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin BP 48, Gif-sur-Yvette, 91190, France
| | - Luis Guillermo Villanueva
- Advanced NEMS Laboratory, Institute of Mechanical Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, 1015, Switzerland
| | - Gustau Catalan
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, Barcelona, 08193, Catalonia, Spain
- ICREA - Institució Catalana de Recerca i Estudis Avançats, Barcelona, 08010, Catalonia
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2
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Wang Z, Shu S, Wei X, Liang R, Ke S, Shu L, Catalan G. Flexophotovoltaic Effect and Above-Band-Gap Photovoltage Induced by Strain Gradients in Halide Perovskites. Phys Rev Lett 2024; 132:086902. [PMID: 38457719 DOI: 10.1103/physrevlett.132.086902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 12/05/2023] [Indexed: 03/10/2024]
Abstract
We have measured the flexophotovoltaic effect of single crystals of halide perovskites MAPbBr_{3} and MAPbI_{3}, as well as the benchmark oxide perovskite SrTiO_{3}. For halide perovskites, the flexophotovoltaic effect is found to be orders of magnitude larger than for SrTiO_{3}, and indeed large enough to induce photovoltages bigger than the band gap. Moreover, we find that in MAPbI_{3} the flexophotovoltaic effect is additional to a native bulk photovoltaic response that is switchable and ferroelectric-like. The results suggest that strain gradient engineering can be a powerful tool to modify the photovoltaic output even in already well-established photovoltaic materials.
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Affiliation(s)
- Zhiguo Wang
- School of Physics and Materials Science, Nanchang University, Nanchang 330031, People's Republic of China
| | - Shengwen Shu
- College of Electrical Engineering and Automation, Fuzhou University, Fuzhou 350108, People's Republic of China
| | - Xiaoyong Wei
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education and International Center for Dielectric Research, Xi'an Jiao Tong University, Xi'an 710049, People's Republic of China
| | - Renhong Liang
- School of Physics and Materials Science, Nanchang University, Nanchang 330031, People's Republic of China
| | - Shanming Ke
- School of Physics and Materials Science, Nanchang University, Nanchang 330031, People's Republic of China
| | - Longlong Shu
- School of Physics and Materials Science, Nanchang University, Nanchang 330031, People's Republic of China
| | - Gustau Catalan
- Institucio Catalana de Recerca i Estudis Avançats (ICREA), Barcelona 08010, Catalonia
- Institut Catala de Nanociencia i Nanotecnologia (ICN2), CSIC-BIST, Campus Universitat Autonoma de Barcelona, Barcelona 08193, Catalonia
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Cho S, Gaponenko I, Cordero-Edwards K, Barceló-Mercader J, Arias I, Kim D, Lichtensteiger C, Yeom J, Musy L, Kim H, Han SM, Catalan G, Paruch P, Hong S. Switchable tribology of ferroelectrics. Nat Commun 2024; 15:387. [PMID: 38195614 PMCID: PMC10776724 DOI: 10.1038/s41467-023-44346-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 12/09/2023] [Indexed: 01/11/2024] Open
Abstract
Switchable tribological properties of ferroelectrics offer an alternative route to visualize and control ferroelectric domains. Here, we observe the switchable friction and wear behavior of ferroelectrics using a nanoscale scanning probe-down domains have lower friction coefficients and show slower wear rates than up domains and can be used as smart masks. This asymmetry is enabled by flexoelectrically coupled polarization in the up and down domains under a sufficiently high contact force. Moreover, we determine that this polarization-sensitive tribological asymmetry is widely applicable across various ferroelectrics with different chemical compositions and crystalline symmetry. Finally, using this switchable tribology and multi-pass patterning with a domain-based dynamic smart mask, we demonstrate three-dimensional nanostructuring exploiting the asymmetric wear rates of up and down domains, which can, furthermore, be scaled up to technologically relevant (mm-cm) size. These findings demonstrate that ferroelectrics are electrically tunable tribological materials at the nanoscale for versatile applications.
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Affiliation(s)
- Seongwoo Cho
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.
- Department of Quantum Matter Physics, University of Geneva, 1211, Geneva, Switzerland.
| | - Iaroslav Gaponenko
- Department of Quantum Matter Physics, University of Geneva, 1211, Geneva, Switzerland
- G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia, 30332, United States of America
| | | | - Jordi Barceló-Mercader
- LaCàN - Mathematical and Computational Modeling, Polytechnic University of Catalonia, Barcelona, 08034, Spain
| | - Irene Arias
- LaCàN - Mathematical and Computational Modeling, Polytechnic University of Catalonia, Barcelona, 08034, Spain
- International Centre for Numerical Methods in Engineering (CIMNE), Barcelona, 08034, Spain
| | - Daeho Kim
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Céline Lichtensteiger
- Department of Quantum Matter Physics, University of Geneva, 1211, Geneva, Switzerland
| | - Jiwon Yeom
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Loïc Musy
- Department of Quantum Matter Physics, University of Geneva, 1211, Geneva, Switzerland
| | - Hyunji Kim
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Seung Min Han
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Gustau Catalan
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), Campus Autonomous University of Barcelona, Bellaterra, 08193, Spain
- Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, 08010, Catalonia
| | - Patrycja Paruch
- Department of Quantum Matter Physics, University of Geneva, 1211, Geneva, Switzerland.
| | - Seungbum Hong
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.
- KAIST Institute for NanoCentury (KINC), Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.
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Liu Y, Niu R, Majchrowski A, Roleder K, Cordero-Edwards K, Cairney JM, Arbiol J, Catalan G. Translational Boundaries as Incipient Ferrielectric Domains in Antiferroelectric PbZrO_{3}. Phys Rev Lett 2023; 130:216801. [PMID: 37295088 DOI: 10.1103/physrevlett.130.216801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 02/26/2023] [Accepted: 04/28/2023] [Indexed: 06/12/2023]
Abstract
In the archetypal antiferroelectric PbZrO_{3}, antiparallel electric dipoles cancel each other, resulting in zero spontaneous polarization at the macroscopic level. Yet in actual hysteresis loops, the cancellation is rarely perfect and some remnant polarization is often observed, suggesting the metastability of polar phases in this material. In this work, using aberration-corrected scanning transmission electron microscopy methods on a PbZrO_{3} single crystal, we uncover the coexistence of the common antiferroelectric phase and a ferrielectric phase featuring an electric dipole pattern of ↓↑↓. This dipole arrangement, predicted by Aramberri et al. to be the ground state of PbZrO_{3} at 0 K, appears at room temperature in the form of translational boundaries. The dual nature of the ferrielectric phase, both a distinct phase and a translational boundary structure, places important symmetry constraints on its growth. These are overcome by sideways motion of the boundaries, which aggregate to form arbitrarily wide stripe domains of the polar phase embedded within the antiferroelectric matrix.
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Affiliation(s)
- Ying Liu
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), Campus Universitat Autonoma de Barcelona, Bellaterra 08193, Spain
| | - Ranming Niu
- School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, New South Wales 2006, Australia
- Australian Centre for Microscopy and Microanalysis, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Andrzej Majchrowski
- Institute of Applied Physics, Military University of Technology, Ulica Kaliskiego 2, 00-908 Warsaw, Poland
| | - Krystian Roleder
- Institute of Physics, University of Silesia, Ulica 75 Pułku Piechoty 1, 41-500 Chorzów, Poland
| | - Kumara Cordero-Edwards
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), Campus Universitat Autonoma de Barcelona, Bellaterra 08193, Spain
| | - Julie M Cairney
- School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, New South Wales 2006, Australia
- Australian Centre for Microscopy and Microanalysis, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Jordi Arbiol
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), Campus Universitat Autonoma de Barcelona, Bellaterra 08193, Spain
- Institut Català de Recerca i Estudis Avançats (ICREA), Barcelona 08010, Catalunya, Spain
| | - Gustau Catalan
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), Campus Universitat Autonoma de Barcelona, Bellaterra 08193, Spain
- Institut Català de Recerca i Estudis Avançats (ICREA), Barcelona 08010, Catalunya, Spain
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5
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Spasojevic I, Santiso J, Caicedo JM, Catalan G, Domingo N. Tunable Molecular Electrodes for Bistable Polarization Screening. Small 2023:e2207799. [PMID: 37066721 DOI: 10.1002/smll.202207799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 02/27/2023] [Indexed: 06/19/2023]
Abstract
The polar discontinuity at any ferroelectric surface creates a depolarizing field that must be screened for the polarization to be stable. In capacitors, screening is done by the electrodes, while in bare ferroelectric surfaces it is typically accomplished by atmospheric adsorbates. Although chemisorbed species can have even better screening efficiency than conventional electrodes, they are subject to unpredictable environmental fluctuations and, moreover, dominant charged species favor one polarity over the opposite. This paper proposes a new screening concept, namely surface functionalization with resonance-hybrid molecules, which combines the predictability and bipolarity of conventional electrodes with the screening efficiency of adsorbates. Thin films of barium titanate (BaTiO3 ) coated with resonant para-aminobenzoic acid (pABA) display increased coercivity for both signs of ferroelectric polarization irrespective of the molecular layer thickness, thanks to the ability of these molecules to swap between different electronic configurations and adapt their surface charge density to the screening needs of the ferroelectric underneath. Because electron delocalization is only in the vertical direction, unlike conventional metals, chemical electrodes allow writing localized domains of different polarity underneath the same electrode. In addition, hybrid capacitors composed of graphene/pABA/ferroelectric have been made with enhanced coercivity compared to pure graphene-electode capacitors.
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Affiliation(s)
- Irena Spasojevic
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, Barcelona, 08193, Spain
- Department of Chemistry, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, 08193, Spain
| | - José Santiso
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, Barcelona, 08193, Spain
| | - José Manuel Caicedo
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, Barcelona, 08193, Spain
| | - Gustau Catalan
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, Barcelona, 08193, Spain
- ICREA- Institució Catalana de Recerca i Estudis Avançats, Catalonia, Barcelona, 08010, Catalonia
| | - Neus Domingo
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, Barcelona, 08193, Spain
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6
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Bugallo D, Langenberg E, Ferreiro-Vila E, Smith EH, Stefani C, Batlle X, Catalan G, Domingo N, Schlom DG, Rivadulla F. Deconvolution of Phonon Scattering by Ferroelectric Domain Walls and Point Defects in a PbTiO 3 Thin Film Deposited in a Composition-Spread Geometry. ACS Appl Mater Interfaces 2021; 13:45679-45685. [PMID: 34523338 DOI: 10.1021/acsami.1c08758] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We present a detailed analysis of the temperature dependence of the thermal conductivity of a ferroelectric PbTiO3 thin film deposited in a composition-spread geometry enabling a continuous range of compositions from ∼25% titanium deficient to ∼20% titanium rich to be studied. By fitting the experimental results to the Debye model we deconvolute and quantify the two main phonon-scattering sources in the system: ferroelectric domain walls (DWs) and point defects. Our results prove that ferroelectric DWs are the main agent limiting the thermal conductivity in this system, not only in the stoichiometric region of the thin film ([Pb]/[Ti] ≈ 1) but also when the concentration of the cation point defects is significant (up to ∼15%). Hence, DWs in ferroelectric materials are a source of phonon scattering at least as effective as point defects. Our results demonstrate the viability and effectiveness of using reconfigurable DWs to control the thermal conductivity in solid-state devices.
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Affiliation(s)
- David Bugallo
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Departamento de Química-Física, Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
| | - Eric Langenberg
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Departamento de Química-Física, Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
- Department de Física de la Matèria Condensada and Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, Barcelona 08028, Spain
| | - Elias Ferreiro-Vila
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Departamento de Química-Física, Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
| | - Eva H Smith
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Christina Stefani
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC, Barcelona Institute of Science and Technology, Campus Universitat Autònoma de Barcelona, Bellaterra, Barcelona 08193 Spain
| | - Xavier Batlle
- Department de Física de la Matèria Condensada and Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, Barcelona 08028, Spain
| | - Gustau Catalan
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC, Barcelona Institute of Science and Technology, Campus Universitat Autònoma de Barcelona, Bellaterra, Barcelona 08193 Spain
| | - Neus Domingo
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC, Barcelona Institute of Science and Technology, Campus Universitat Autònoma de Barcelona, Bellaterra, Barcelona 08193 Spain
| | - Darrell G Schlom
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853, United States
- Leibniz-Institut für Kristallzüchtung, Max-Born-Strasse 2, 12489 Berlin, Germany
| | - Francisco Rivadulla
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Departamento de Química-Física, Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
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Sandiumenge F, Rodríguez L, Pruneda M, Magén C, Santiso J, Catalan G. Metallic Diluted Dimerization in VO 2 Tweeds. Adv Mater 2021; 33:e2004374. [PMID: 33501746 DOI: 10.1002/adma.202004374] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 01/03/2021] [Indexed: 06/12/2023]
Abstract
The observation of electronic phase separation textures in vanadium dioxide, a prototypical electron-correlated oxide, has recently added new perspectives on the long standing debate about its metal-insulator transition and its applications. Yet, the lack of atomically resolved information on phases accompanying such complex patterns still hinders a comprehensive understanding of the transition and its implementation in practical devices. In this work, atomic resolution imaging and spectroscopy unveils the existence of ferroelastic tweed structures on ≈5 nm length scales, well below the resolution limit of currently used spectroscopic imaging techniques. Moreover, density functional theory calculations show that this pretransitional fine-scale tweed, which on average looks and behaves like the standard metallic rutile phase, is in fact weaved by semi-dimerized chains of vanadium in a new monoclinic phase that represents a structural bridge to the monoclinic insulating ground state. These observations provide a multiscale perspective for the interpretation of existing data, whereby phase coexistence and structural intermixing can occur all the way down to the atomic scale.
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Affiliation(s)
- Felip Sandiumenge
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus de la UAB, Bellaterra, Catalonia, 08193, Spain
| | - Laura Rodríguez
- ICN2 (Institut Catala de Nanociencia i Nanotecnologia) BIST-CSIC, Bellaterra, Catalonia, 08193, Spain
| | - Miguel Pruneda
- ICN2 (Institut Catala de Nanociencia i Nanotecnologia) BIST-CSIC, Bellaterra, Catalonia, 08193, Spain
| | - César Magén
- Instituto de Ciencia de Materiales de Aragón (ICMA), Universidad de Zaragoza - CSIC, Departamento de Física de la Materia Condensada, Zaragoza, 50009, Spain
- Laboratorio de Microscopías Avanzadas (LMA) - Instituto de Nanociencia de Aragón (INA), Universidad de Zaragoza, Zaragoza, 50018, Spain
| | - José Santiso
- ICN2 (Institut Catala de Nanociencia i Nanotecnologia) BIST-CSIC, Bellaterra, Catalonia, 08193, Spain
| | - Gustau Catalan
- ICN2 (Institut Catala de Nanociencia i Nanotecnologia) BIST-CSIC, Bellaterra, Catalonia, 08193, Spain
- ICREA (Institució Catalana de Recerca i Estudis Avançats), Barcelona, 08010, Spain
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8
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Shu L, Ke S, Fei L, Huang W, Wang Z, Gong J, Jiang X, Wang L, Li F, Lei S, Rao Z, Zhou Y, Zheng RK, Yao X, Wang Y, Stengel M, Catalan G. Photoflexoelectric effect in halide perovskites. Nat Mater 2020; 19:605-609. [PMID: 32313265 DOI: 10.1038/s41563-020-0659-y] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 03/06/2020] [Indexed: 05/28/2023]
Abstract
Harvesting environmental energy to generate electricity is a key scientific and technological endeavour of our time. Photovoltaic conversion and electromechanical transduction are two common energy-harvesting mechanisms based on, respectively, semiconducting junctions and piezoelectric insulators. However, the different material families on which these transduction phenomena are based complicate their integration into single devices. Here we demonstrate that halide perovskites, a family of highly efficient photovoltaic materials1-3, display a photoflexoelectric effect whereby, under a combination of illumination and oscillation driven by a piezoelectric actuator, they generate orders of magnitude higher flexoelectricity than in the dark. We also show that photoflexoelectricity is not exclusive to halides but a general property of semiconductors that potentially enables simultaneous electromechanical and photovoltaic transduction and harvesting in unison from multiple energy inputs.
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Affiliation(s)
- Longlong Shu
- School of Materials Science and Engineering, Nanchang University, Nanchang, People's Republic of China.
| | - Shanming Ke
- School of Materials Science and Engineering, Nanchang University, Nanchang, People's Republic of China
| | - Linfeng Fei
- School of Materials Science and Engineering, Nanchang University, Nanchang, People's Republic of China
| | - Wenbin Huang
- The State Key Lab of Mechanical Transmissions, Chongqing University, Chongqing, People's Republic of China
| | - Zhiguo Wang
- The State Key Lab of Mechanical Transmissions, Chongqing University, Chongqing, People's Republic of China
| | - Jinhui Gong
- School of Materials Science and Engineering, Nanchang University, Nanchang, People's Republic of China
| | - Xiaoning Jiang
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC, USA
| | - Li Wang
- School of Materials Science and Engineering, Nanchang University, Nanchang, People's Republic of China
| | - Fei Li
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education and International Center for Dielectric Research, Xi'an Jiao Tong University, Xi'an, People's Republic of China
| | - Shuijin Lei
- School of Materials Science and Engineering, Nanchang University, Nanchang, People's Republic of China
| | - Zhenggang Rao
- School of Materials Science and Engineering, Nanchang University, Nanchang, People's Republic of China
| | - Yangbo Zhou
- School of Materials Science and Engineering, Nanchang University, Nanchang, People's Republic of China
| | - Ren-Kui Zheng
- School of Materials Science and Engineering, Nanchang University, Nanchang, People's Republic of China
| | - Xi Yao
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education and International Center for Dielectric Research, Xi'an Jiao Tong University, Xi'an, People's Republic of China
| | - Yu Wang
- School of Materials Science and Engineering, Nanchang University, Nanchang, People's Republic of China
| | - Massimiliano Stengel
- Institucio Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Catalonia
- Institut de Ciencia de Materials de Barcelona (ICMAB), Consejo Superior de Investigaciones Científicas (CSIC), Campus Universitat Autonoma de Barcelona, Barcelona, Catalonia
| | - Gustau Catalan
- Institucio Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Catalonia.
- Institut Catala de Nanociencia i Nanotecnologia (ICN2), Consejo Superior de Investigaciones Científicas and The Barcelona Institute of Science and Technology (CSIC-BIST), Campus Universitat Autonoma de Barcelona, Barcelona, Catalonia.
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9
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Langenberg E, Paik H, Smith EH, Nair HP, Hanke I, Ganschow S, Catalan G, Domingo N, Schlom DG. Strain-Engineered Ferroelastic Structures in PbTiO 3 Films and Their Control by Electric Fields. ACS Appl Mater Interfaces 2020; 12:20691-20703. [PMID: 32292024 DOI: 10.1021/acsami.0c04381] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We study the interplay between epitaxial strain, film thickness, and electric field in the creation, modification, and design of distinct ferroelastic structures in PbTiO3 thin films. Strain and thickness greatly affect the structures formed, providing a two-variable parameterization of the resulting self-assembly. Under applied electric fields, these strain-engineered ferroelastic structures are highly malleable, especially when a/c and a1/a2 superdomains coexist. To reconfigure the ferroelastic structures and achieve self-assembled nanoscale-ordered morphologies, pure ferroelectric switching of individual c-domains within the a/c superdomains is essential. The stability, however, of the electrically written ferroelastic structures is in most cases ephemeral; the speed of the relaxation process depends sensitively on strain and thickness. Only under low tensile strain-as is the case for PbTiO3 on GdScO3-and below a critical thickness do the electrically created a/c superdomain structures become stable for days or longer, making them relevant for reconfigurable nanoscale electronics or nonvolatile electromechanical applications.
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Affiliation(s)
- Eric Langenberg
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Hanjong Paik
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Eva H Smith
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Hari P Nair
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Isabelle Hanke
- Leibniz-Institut für Kristallzüchtung, Max-Born-Straße 2, 12489 Berlin, Germany
| | - Steffen Ganschow
- Leibniz-Institut für Kristallzüchtung, Max-Born-Straße 2, 12489 Berlin, Germany
| | - Gustau Catalan
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC, Barcelona Institute of Science and Technology, Campus Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
| | - Neus Domingo
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC, Barcelona Institute of Science and Technology, Campus Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
| | - Darrell G Schlom
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853, United States
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10
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Langenberg E, Saha D, Holtz ME, Wang JJ, Bugallo D, Ferreiro-Vila E, Paik H, Hanke I, Ganschow S, Muller DA, Chen LQ, Catalan G, Domingo N, Malen J, Schlom DG, Rivadulla F. Ferroelectric Domain Walls in PbTiO 3 Are Effective Regulators of Heat Flow at Room Temperature. Nano Lett 2019; 19:7901-7907. [PMID: 31596599 DOI: 10.1021/acs.nanolett.9b02991] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Achieving efficient spatial modulation of phonon transmission is an essential step on the path to phononic circuits using "phonon currents". With their intrinsic and reconfigurable interfaces, domain walls (DWs), ferroelectrics are alluring candidates to be harnessed as dynamic heat modulators. This paper reports the thermal conductivity of single-crystal PbTiO3 thin films over a wide variety of epitaxial-strain-engineered ferroelectric domain configurations. The phonon transport is proved to be strongly affected by the density and type of DWs, achieving a 61% reduction of the room-temperature thermal conductivity compared to the single-domain scenario. The thermal resistance across the ferroelectric DWs is obtained, revealing a very high value (≈5.0 × 10-9 K m2 W-1), comparable to grain boundaries in oxides, explaining the strong modulation of the thermal conductivity in PbTiO3. This low thermal conductance of the DWs is ascribed to the structural mismatch and polarization gradient found between the different types of domains in the PbTiO3 films, resulting in a structural inhomogeneity that extends several unit cells around the DWs. These findings demonstrate the potential of ferroelectric DWs as efficient regulators of heat flow in one single material, overcoming the complexity of multilayers systems and the uncontrolled distribution of grain boundaries, paving the way for applications in phononics.
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Affiliation(s)
- Eric Langenberg
- Department of Materials Science and Engineering , Cornell University , Ithaca , New York 14853 , United States
- Centro Singular de Investigación en Quı́mica Biolıoxica e Materiais Moleculares (CiQUS), Departmento de Quı́mica-Fı́sica , Universidade de Santiago de Compostela , Santiago de Compostela 15782 , Spain
| | - Dipanjan Saha
- Mechanical Engineering Department , Carnegie Mellon University , Pittsburgh , Pennsylvania 15213 , United States
| | - Megan E Holtz
- Department of Materials Science and Engineering , Cornell University , Ithaca , New York 14853 , United States
- School of Applied and Engineering Physics , Cornell University , Ithaca , New York 14853 , United States
| | - Jian-Jun Wang
- Department of Materials Science and Engineering , Pennsylvania State University , State College , Pennsylvania 16802 , United States
| | - David Bugallo
- Centro Singular de Investigación en Quı́mica Biolıoxica e Materiais Moleculares (CiQUS), Departmento de Quı́mica-Fı́sica , Universidade de Santiago de Compostela , Santiago de Compostela 15782 , Spain
| | - Elias Ferreiro-Vila
- Centro Singular de Investigación en Quı́mica Biolıoxica e Materiais Moleculares (CiQUS), Departmento de Quı́mica-Fı́sica , Universidade de Santiago de Compostela , Santiago de Compostela 15782 , Spain
| | - Hanjong Paik
- Department of Materials Science and Engineering , Cornell University , Ithaca , New York 14853 , United States
| | - Isabelle Hanke
- Leibniz-Institut für Kristallzüchtung , Max-Born-Straße 2 , 12489 Berlin , Germany
| | - Steffen Ganschow
- Leibniz-Institut für Kristallzüchtung , Max-Born-Straße 2 , 12489 Berlin , Germany
| | - David A Muller
- School of Applied and Engineering Physics , Cornell University , Ithaca , New York 14853 , United States
| | - Long-Qing Chen
- Department of Materials Science and Engineering , Pennsylvania State University , State College , Pennsylvania 16802 , United States
| | - Gustau Catalan
- CSIC, Barcelona Institute of Science and Technology, Campus Universitat Autònoma de Barcelona , Catalan Institute of Nanoscience and Nanotechnology (ICN2) , 08193 Bellaterra , Spain
| | - Neus Domingo
- CSIC, Barcelona Institute of Science and Technology, Campus Universitat Autònoma de Barcelona , Catalan Institute of Nanoscience and Nanotechnology (ICN2) , 08193 Bellaterra , Spain
| | - Jonathan Malen
- Mechanical Engineering Department , Carnegie Mellon University , Pittsburgh , Pennsylvania 15213 , United States
| | - Darrell G Schlom
- Department of Materials Science and Engineering , Cornell University , Ithaca , New York 14853 , United States
- Kavli Institute at Cornell for Nanoscale Science , Ithaca , New York 14853 , United States
| | - Francisco Rivadulla
- Centro Singular de Investigación en Quı́mica Biolıoxica e Materiais Moleculares (CiQUS), Departmento de Quı́mica-Fı́sica , Universidade de Santiago de Compostela , Santiago de Compostela 15782 , Spain
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11
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Everhardt AS, Damerio S, Zorn JA, Zhou S, Domingo N, Catalan G, Salje EKH, Chen LQ, Noheda B. Periodicity-Doubling Cascades: Direct Observation in Ferroelastic Materials. Phys Rev Lett 2019; 123:087603. [PMID: 31491229 DOI: 10.1103/physrevlett.123.087603] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 05/06/2019] [Indexed: 06/10/2023]
Abstract
Very sensitive responses to external forces are found near phase transitions. However, transition dynamics and preequilibrium phenomena are difficult to detect and control. We have observed that the equilibrium domain structure following a phase transition in ferroelectric and ferroelastic BaTiO_{3} is attained by halving of the domain periodicity multiple times. The process is reversible, with periodicity doubling as temperature is increased. This observation is reminiscent of the period-doubling cascades generally observed during bifurcation phenomena, and, thus, it conforms to the "spatial chaos" regime earlier proposed by Jensen and Bak [Phys. Scr. T 9, 64 (1985)PHSTER0281-184710.1088/0031-8949/1985/T9/009] for systems with competing spatial modulations.
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Affiliation(s)
- Arnoud S Everhardt
- Zernike Institute for Advanced Materials, University of Groningen, 9747AG- Groningen, Netherlands
| | - Silvia Damerio
- Zernike Institute for Advanced Materials, University of Groningen, 9747AG- Groningen, Netherlands
| | - Jacob A Zorn
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Silang Zhou
- Zernike Institute for Advanced Materials, University of Groningen, 9747AG- Groningen, Netherlands
| | - Neus Domingo
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), 08193 Barcelona, Catalonia, Spain
| | - Gustau Catalan
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), 08193 Barcelona, Catalonia, Spain
- ICREA, 08193 Barcelona, Catalonia, Spain
| | - Ekhard K H Salje
- University of Cambridge, Cambridge, Oxford OX1 3AN, United Kingdom
| | - Long-Qing Chen
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Beatriz Noheda
- Zernike Institute for Advanced Materials, University of Groningen, 9747AG- Groningen, Netherlands
- CogniGron Center, University of Groningen, 9747AG- Groningen, Netherlands
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12
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Cordero-Edwards K, Kianirad H, Canalias C, Sort J, Catalan G. Flexoelectric Fracture-Ratchet Effect in Ferroelectrics. Phys Rev Lett 2019; 122:135502. [PMID: 31012630 DOI: 10.1103/physrevlett.122.135502] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 02/20/2019] [Indexed: 06/09/2023]
Abstract
The propagation front of a crack generates large strain gradients and it is therefore a strong source of gradient-induced polarization (flexoelectricity). Herein, we demonstrate that, in piezoelectric materials, a consequence of flexoelectricity is that crack propagation is helped or hindered depending on whether it is parallel or antiparallel to the piezoelectric polar axis. The discovery of crack propagation asymmetry proves that fracture physics cannot be assumed to be symmetric in polar materials, and indicates that flexoelectricity should be incorporated in any realistic model.
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Affiliation(s)
- Kumara Cordero-Edwards
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Catalonia
- DPMC-MaNEP, Université de Genéve, Quai Ernest-Ansermet 24, 1211 Geneva, Switzerland
| | - Hoda Kianirad
- Department of Applied Physics, KTH-Royal Institute of Technology, Roslagstullsbacken 21, 10691 Stockholm, Sweden
| | - Carlota Canalias
- Department of Applied Physics, KTH-Royal Institute of Technology, Roslagstullsbacken 21, 10691 Stockholm, Sweden
| | - Jordi Sort
- Departament de Física, Universitat Autònoma de Barcelona (UAB), Edifici Cc, E-08193 Bellaterra, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluís Companys 23, E-08010 Barcelona, Catalonia
| | - Gustau Catalan
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Catalonia
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluís Companys 23, E-08010 Barcelona, Catalonia
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13
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Abdollahi A, Domingo N, Arias I, Catalan G. Converse flexoelectricity yields large piezoresponse force microscopy signals in non-piezoelectric materials. Nat Commun 2019; 10:1266. [PMID: 30894544 PMCID: PMC6427004 DOI: 10.1038/s41467-019-09266-y] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 02/20/2019] [Indexed: 11/09/2022] Open
Abstract
Converse flexoelectricity is a mechanical stress induced by an electric polarization gradient. It can appear in any material, irrespective of symmetry, whenever there is an inhomogeneous electric field distribution. This situation invariably happens in piezoresponse force microscopy (PFM), which is a technique whereby a voltage is delivered to the tip of an atomic force microscope in order to stimulate and probe piezoelectricity at the nanoscale. While PFM is the premier technique for studying ferroelectricity and piezoelectricity at the nanoscale, here we show, theoretically and experimentally, that large effective piezoelectric coefficients can be measured in non-piezoelectric dielectrics due to converse flexoelectricity.
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Affiliation(s)
- Amir Abdollahi
- Laboratori de Càlcul Numèric (LaCàN), Universitat Politècnica de Catalunya (UPC), Campus Nord UPC-C2, E-08034, Barcelona, Spain.
| | - Neus Domingo
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, 08193, Barcelona, Spain.
| | - Irene Arias
- Laboratori de Càlcul Numèric (LaCàN), Universitat Politècnica de Catalunya (UPC), Campus Nord UPC-C2, E-08034, Barcelona, Spain
| | - Gustau Catalan
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, 08193, Barcelona, Spain.,ICREA-Institut Catala de Recerca i Estudis Avançats, 08010 Barcelona, Catalonia, Spain
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14
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Abstract
The origin of "giant" flexoelectricity, orders of magnitude larger than theoretically predicted, yet frequently observed, is under intense scrutiny. There is mounting evidence correlating giant flexoelectriclike effects with parasitic piezoelectricity, but it is not clear how piezoelectricity (polarization generated by strain) manages to imitate flexoelectricity (polarization generated by strain gradient) in typical beam-bending experiments, since in a bent beam the net strain is zero. In addition piezoelectricity changes sign under space inversion but giant flexoelectricity is insensitive to space inversion, seemingly contradicting a piezoelectric origin. Here we show that, if a piezoelectric material has its piezoelectric coefficient asymmetrically distributed across the sample, it will generate a nonzero bending-induced polarization impossible to distinguish from true flexoelectricity even by inverting the sample. The effective flexoelectric coefficient caused by piezoelectricity is functionally identical to, and often larger than, intrinsic flexoelectricity: our calculations show that, for standard perovskite ferroelectrics, even a tiny gradient of piezoelectricity (1% variation of piezoelectric coefficient across 1 mm) is sufficient to yield a giant effective flexoelectric coefficient of 1 μC/m, three orders of magnitude larger than the intrinsic expectation value.
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Affiliation(s)
- Amir Abdollahi
- Laboratori de Càlcul Numèric (LaCàN), Universitat Politècnica de Catalunya (UPC), Campus Nord UPC-C2, E-08034 Barcelona, Catalonia, Spain
| | - Fabián Vásquez-Sancho
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, 08193 Barcelona, Catalonia, Spain and Centro de Investigación en Ciencia e Ingeniera de Materiales, Universidad de Costa Rica, San José 11501, Costa Rica
| | - Gustau Catalan
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, 08193 Barcelona, Catalonia, Spain and ICREA-Institut Catala de Recerca I Estudis Avançats, Barcelona, Catalonia, Spain
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15
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16
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Abstract
Bones generate electricity under pressure, and this electromechanical behavior is thought to be essential for bone's self-repair and remodeling properties. The origin of this response is attributed to the piezoelectricity of collagen, which is the main structural protein of bones. In theory, however, any material can also generate voltages in response to strain gradients, thanks to the property known as flexoelectricity. In this work, the flexoelectricity of bone and pure bone mineral (hydroxyapatite) are measured and found to be of the same order of magnitude; the quantitative similarity suggests that hydroxyapatite flexoelectricity is the main source of bending-induced polarization in cortical bone. In addition, the measured flexoelectric coefficients are used to calculate the (flexo)electric fields generated by cracks in bone mineral. The results indicate that crack-generated flexoelectricity is theoretically large enough to induce osteocyte apoptosis and thus initiate the crack-healing process, suggesting a central role of flexoelectricity in bone repair and remodeling.
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Affiliation(s)
- Fabian Vasquez-Sancho
- Institut Català de Nanociencia i Nanotecnologia (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, 08193, Barcelona, Catalonia, Spain
- Centro de Investigación en Ciencia e Ingeniería de Materiales (CICIMA), Universidad de Costa Rica, San José, 11501, Costa Rica
| | - Amir Abdollahi
- Laboratori de Càlcul Numèric (LaCàN), Universitat Politècnica de Catalunya (UPC), Campus Nord UPC-C2, E-08034, Barcelona, Spain
| | - Dragan Damjanovic
- Ecole Politechnique Federale de Lausanne (EPFL), Lausanne, CH-1015, Switzerland
| | - Gustau Catalan
- Institut Català de Nanociencia i Nanotecnologia (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, 08193, Barcelona, Catalonia, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluís Companys 23, E-08010, Barcelona, Catalonia, Spain
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17
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Cordero-Edwards K, Domingo N, Abdollahi A, Sort J, Catalan G. Ferroelectrics as Smart Mechanical Materials. Adv Mater 2017; 29:1702210. [PMID: 28730658 DOI: 10.1002/adma.201702210] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 06/09/2017] [Indexed: 06/07/2023]
Abstract
The mechanical properties of materials are insensitive to space inversion, even when they are crystallographically asymmetric. In practice, this means that turning a piezoelectric crystal upside down or switching the polarization of a ferroelectric should not change its mechanical response. Strain gradients, however, introduce an additional source of asymmetry that has mechanical consequences. Using nanoindentation and contact-resonance force microscopy, this study demonstrates that the mechanical response to indentation of a uniaxial ferroelectric (LiNbO3 ) does change when its polarity is switched, and use this mechanical asymmetry both to quantify its flexoelectricity and to mechanically read the sign of its ferroelectric domains.
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Affiliation(s)
- Kumara Cordero-Edwards
- Institut Català de Nanociencia i Nanotecnologia (ICN2), CSIC, and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, E-08193, Barcelona, Spain
| | - Neus Domingo
- Institut Català de Nanociencia i Nanotecnologia (ICN2), CSIC, and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, E-08193, Barcelona, Spain
| | - Amir Abdollahi
- Laboratori de Càlcul Numèric (LaCàN), Universitat Politècnica de Catalunya (UPC), Campus Nord UPC-C2, E-08034, Barcelona, Spain
| | - Jordi Sort
- Departament de Física, Universitat Autònoma de Barcelona (UAB), Edifici Cc, E-0819, Bellaterra, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluís Companys 23, E-08010, Barcelona, Spain
| | - Gustau Catalan
- Institut Català de Nanociencia i Nanotecnologia (ICN2), CSIC, and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, E-08193, Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluís Companys 23, E-08010, Barcelona, Spain
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18
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Zubko P, Lu H, Bark CW, Martí X, Santiso J, Eom CB, Catalan G, Gruverman A. On the persistence of polar domains in ultrathin ferroelectric capacitors. J Phys Condens Matter 2017; 29:284001. [PMID: 28593933 DOI: 10.1088/1361-648x/aa73c3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The instability of ferroelectric ordering in ultra-thin films is one of the most important fundamental issues pertaining realization of a number of electronic devices with enhanced functionality, such as ferroelectric and multiferroic tunnel junctions or ferroelectric field effect transistors. In this paper, we investigate the polarization state of archetypal ultrathin (several nanometres) ferroelectric heterostructures: epitaxial single-crystalline BaTiO3 films sandwiched between the most habitual perovskite electrodes, SrRuO3, on top of the most used perovskite substrate, SrTiO3. We use a combination of piezoresponse force microscopy, dielectric measurements and structural characterization to provide conclusive evidence for the ferroelectric nature of the relaxed polarization state in ultrathin BaTiO3 capacitors. We show that even the high screening efficiency of SrRuO3 electrodes is still insufficient to stabilize polarization in SrRuO3/BaTiO3/SrRuO3 heterostructures at room temperature. We identify the key role of domain wall motion in determining the macroscopic electrical properties of ultrathin capacitors and discuss their dielectric response in the light of the recent interest in negative capacitance behaviour.
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Affiliation(s)
- Pavlo Zubko
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, 17-19 Gordon Street, London WC1H 0AH, United Kingdom
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19
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Pérez-Tomás A, Lira-Cantú M, Catalan G. Above-Bandgap Photovoltages in Antiferroelectrics. Adv Mater 2016; 28:9644-9647. [PMID: 27629252 DOI: 10.1002/adma.201603176] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 07/27/2016] [Indexed: 06/06/2023]
Abstract
The first antiferroelectric solar cell is presented. This study shows that antiferroelectric thin-film photovoltaic current can be switched on when biased into the polar phase to generate abovebandgap photovoltages in excess of 100 V and photovoltaic fields of several megavolts per centimeter, the largest ever measured for any material.
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Affiliation(s)
- Amador Pérez-Tomás
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, 08193, Barcelona, Spain
| | - Monica Lira-Cantú
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, 08193, Barcelona, Spain
| | - Gustau Catalan
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, 08193, Barcelona, Spain
- Institut Català de Recerca i Estudis Avançats (ICREA), Barcelona, 08010, Catalonia, Spain
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20
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Bhaskar UK, Banerjee N, Abdollahi A, Wang Z, Schlom DG, Rijnders G, Catalan G. A flexoelectric microelectromechanical system on silicon. Nat Nanotechnol 2016; 11:263-266. [PMID: 26571008 DOI: 10.1038/nnano.2015.260] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 10/07/2015] [Indexed: 06/05/2023]
Abstract
Flexoelectricity allows a dielectric material to polarize in response to a mechanical bending moment and, conversely, to bend in response to an electric field. Compared with piezoelectricity, flexoelectricity is a weak effect of little practical significance in bulk materials. However, the roles can be reversed at the nanoscale. Here, we demonstrate that flexoelectricity is a viable route to lead-free microelectromechanical and nanoelectromechanical systems. Specifically, we have fabricated a silicon-compatible thin-film cantilever actuator with a single flexoelectrically active layer of strontium titanate with a figure of merit (curvature divided by electric field) of 3.33 MV(-1), comparable to that of state-of-the-art piezoelectric bimorph cantilevers.
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Affiliation(s)
- Umesh Kumar Bhaskar
- ICN2 - Institut Catala de Nanociencia i Nanotecnologia, CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, Barcelona 08193, Spain
| | - Nirupam Banerjee
- Faculty of Science and Technology and MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, AE Enschede 7500, The Netherlands
| | - Amir Abdollahi
- ICN2 - Institut Catala de Nanociencia i Nanotecnologia, CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, Barcelona 08193, Spain
| | - Zhe Wang
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA
| | - Darrell G Schlom
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853, USA
| | - Guus Rijnders
- Faculty of Science and Technology and MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, AE Enschede 7500, The Netherlands
| | - Gustau Catalan
- ICN2 - Institut Catala de Nanociencia i Nanotecnologia, CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, Barcelona 08193, Spain
- ICREA - Institucio Catalana de Recerca i Estudis Avançats, Barcelona 08010, Spain
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21
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Bhaskar UK, Banerjee N, Abdollahi A, Solanas E, Rijnders G, Catalan G. Flexoelectric MEMS: towards an electromechanical strain diode. Nanoscale 2016; 8:1293-1298. [PMID: 26676467 DOI: 10.1039/c5nr06514c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Piezoelectricity and flexoelectricity are two independent but not incompatible forms of electromechanical response exhibited by nanoscale ferroelectrics. Here, we show that flexoelectricity can either enhance or suppress the piezoelectric response of the cantilever depending on the ferroelectric polarity and lead to a diode-like asymmetric (two-state) electromechanical response.
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Affiliation(s)
- U K Bhaskar
- ICN2 - Institut Catala de Nanociencia i Nanotecnologia, CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, 08193 Bellaterra, Barcelona, Spain.
| | - N Banerjee
- Faculty of Science and Technology and MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - A Abdollahi
- ICN2 - Institut Catala de Nanociencia i Nanotecnologia, CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, 08193 Bellaterra, Barcelona, Spain.
| | - E Solanas
- Lyncée Tec SA, PSE-A, CH-1015 Lausanne, Switzerland
| | - G Rijnders
- Faculty of Science and Technology and MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - G Catalan
- ICN2 - Institut Catala de Nanociencia i Nanotecnologia, CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, 08193 Bellaterra, Barcelona, Spain. and ICREA - Institucio Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain
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22
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Narvaez J, Saremi S, Hong J, Stengel M, Catalan G. Large Flexoelectric Anisotropy in Paraelectric Barium Titanate. Phys Rev Lett 2015; 115:037601. [PMID: 26230825 DOI: 10.1103/physrevlett.115.037601] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Indexed: 06/04/2023]
Abstract
The bending-induced polarization of barium titanate single crystals has been measured with an aim to elucidate the origin of the large difference between theoretically predicted and experimentally measured flexoelectricity in this material. The results indicate that part of the difference is due to polar regions (short-range order) that exist above T(C) and up to T*≈200-225 °C. Above T*, however, the flexovoltage coefficient still shows an unexpectedly large anisotropy for a cubic material, with (001)-oriented crystals displaying 10 times more flexoelectricity than (111)-oriented crystals. Theoretical analysis shows that this anisotropy cannot be a bulk property, and we therefore interpret it as indirect evidence for the theoretically predicted but experimentally elusive contribution of surface piezoelectricity to macroscopic bending-induced polarization.
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Affiliation(s)
- Jackeline Narvaez
- ICN2-Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra (Barcelona), Spain
- CSIC-Consejo Superior de Investigaciones Cientificas, ICN2 Building, Campus UAB, 08193 Bellaterra (Barcelona), Spain
| | - Sahar Saremi
- ICN2-Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra (Barcelona), Spain
| | - Jiawang Hong
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Massimiliano Stengel
- Institut de Ciencia de Materials de Barcelona (ICMAB-CSIC), Campus UAB, 08193 Bellaterra (Barcelona), Spain
- ICREA-Institucio Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain
| | - Gustau Catalan
- ICN2-Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra (Barcelona), Spain
- ICREA-Institucio Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain
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23
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Sharma P, Ryu S, Burton JD, Paudel TR, Bark CW, Huang Z, Tsymbal EY, Catalan G, Eom CB, Gruverman A. Mechanical Tuning of LaAlO3/SrTiO3 Interface Conductivity. Nano Lett 2015; 15:3547-3551. [PMID: 25860855 DOI: 10.1021/acs.nanolett.5b01021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In recent years, complex-oxide heterostructures and their interfaces have become the focus of significant research activity, primarily driven by the discovery of emerging states and functionalities that open up opportunities for the development of new oxide-based nanoelectronic devices. The highly conductive state at the interface between insulators LaAlO3 and SrTiO3 is a prime example of such emergent functionality, with potential application in high electron density transistors. In this report, we demonstrate a new paradigm for voltage-free tuning of LaAlO3/SrTiO3 (LAO/STO) interface conductivity, which involves the mechanical gating of interface conductance through stress exerted by the tip of a scanning probe microscope. The mechanical control of channel conductivity and the long retention time of the induced resistance states enable transistor functionality with zero gate voltage.
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Affiliation(s)
| | - S Ryu
- ‡Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | | | | | - C W Bark
- ‡Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | | | | | - G Catalan
- ∥ICREA-Institut Catala de Recerca i Estudis Avançats, Barcelona, Spain
- ⊥ICN2-Institut Catala de Nanociencia i Nanotecnologia, Campus de Bellaterra, Barcelona, Spain
| | - C B Eom
- ‡Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
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24
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Domingo N, López-Mir L, Paradinas M, Holy V, Železný J, Yi D, Suresha SJ, Liu J, Rayan Serrao C, Ramesh R, Ocal C, Martí X, Catalan G. Giant reversible nanoscale piezoresistance at room temperature in Sr2IrO4 thin films. Nanoscale 2015; 7:3453-3459. [PMID: 25649123 DOI: 10.1039/c4nr06954d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Layered iridates have been the subject of intense scrutiny on account of their unusually strong spin-orbit coupling, which opens up a narrow bandgap in a material that would otherwise be a metal. This insulating state is very sensitive to external perturbations. Here, we show that vertical compression at the nanoscale, delivered using the tip of a standard scanning probe microscope, is capable of inducing a five orders of magnitude change in the room temperature resistivity of Sr2IrO4. The extreme sensitivity of the electronic structure to anisotropic deformations opens up a new angle of interest on this material, with the giant and fully reversible perpendicular piezoresistance rendering iridates as promising materials for room temperature piezotronic devices.
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Affiliation(s)
- Neus Domingo
- ICN2-Institut Català de Nanociència i Nanotecnologia, Campus Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
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25
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Affiliation(s)
- Gustau Catalan
- ICREA-Institució Catalana de Recerca i Estudis Avançats and ICN2-Institut Català de Nanociència i Nanotecnologia, Campus UAB, Bellaterra, Barcelona 08193, Spain
| | - David Jiménez
- Departament d'Enginyeria Electrònica, Escola d'Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
| | - Alexei Gruverman
- Department of Physics and Astronomy, and Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, Nebraska 68588, USA
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26
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Abstract
Ferroelectric materials are characterized by a permanent electric dipole that can be reversed through the application of an external voltage, but a strong intrinsic coupling between polarization and deformation also causes all ferroelectrics to be piezoelectric, leading to applications in sensors and high-displacement actuators. A less explored property is flexoelectricity, the coupling between polarization and a strain gradient. We demonstrate that the stress gradient generated by the tip of an atomic force microscope can mechanically switch the polarization in the nanoscale volume of a ferroelectric film. Pure mechanical force can therefore be used as a dynamic tool for polarization control and may enable applications in which memory bits are written mechanically and read electrically.
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Affiliation(s)
- H Lu
- Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
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27
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He Q, Yeh CH, Yang JC, Singh-Bhalla G, Liang CW, Chiu PW, Catalan G, Martin LW, Chu YH, Scott JF, Ramesh R. Magnetotransport at domain walls in BiFeO3. Phys Rev Lett 2012; 108:067203. [PMID: 22401116 DOI: 10.1103/physrevlett.108.067203] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Indexed: 05/31/2023]
Abstract
Domain walls in multiferroics can exhibit intriguing behaviors that are significantly different from the bulk of the material. We investigate strong magnetoresistance in domain walls of the model multiferroic BiFeO3 by probing ordered arrays of 109° domain walls with temperature- and magnetic-field-dependent transport. We observe temperature-dependent variations in the transport mechanism and magnetoresistances as large as 60%. These results suggest that by locally breaking the symmetry of a material, such as at domain walls and structural interfaces, one can induce emergent behavior with properties that deviate significantly from the bulk.
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Affiliation(s)
- Q He
- Department of Physics, University of California, Berkeley, California 94720, USA
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28
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Sardar K, Hong J, Catalan G, Biswas PK, Lees MR, Walton RI, Scott JF, Redfern SAT. Structural, spectroscopic, magnetic and electrical characterization of Ca-doped polycrystalline bismuth ferrite, Bi(1-x)Ca(x)FeO(3-x/2) (x ≤ 0.1). J Phys Condens Matter 2012; 24:045905. [PMID: 22214552 DOI: 10.1088/0953-8984/24/4/045905] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The crystal structure and physical properties of multiferroic polycrystalline Ca(2+)-doped BiFeO(3) samples have been investigated. The present experimental investigation suggests that Bi(1-x)Ca(x)FeO(3-x/2) (x ≤ 0.1) can be considered as a solid solution between BiFeO(3) and CaFeO(2.5). The oxidation state of Fe in these materials is + 3 and charge balance occurs through the creation of oxygen vacancies. For each composition, two structural phase transitions are revealed as anomalies in the variable-temperature in situ x-ray diffraction data which is consistent with the well-established high-temperature structural transformation in pure BiFeO(3). All compositions studied show antiferromagnetic behaviour along with a ferromagnetic component that increases with Ca(2+) doping. The resistivities of the Bi(1-x)Ca(x)FeO(3-x/2) samples at room temperature are of the order of 10(9) Ω cm and decrease with increasing Ca(2+) content. Arrhenius plots of the resistivity show two distinct linear regions with activation energies in the range of 0.4-0.7 and 0.03-0.16 eV. A correlation has been established between the critical temperatures associated with the structural phase transitions and the multiferroic properties. A composition of x = 0.085 is predicted to show maximum magneto-electric coupling.
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29
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Carpenter MA, Bryson JFJ, Catalan G, Howard CJ. Elastic and anelastic relaxations in the relaxor ferroelectric Pb(Mg1/3Nb2/3)O3: I. Strain analysis and a static order parameter. J Phys Condens Matter 2012; 24:045901. [PMID: 22185960 DOI: 10.1088/0953-8984/24/4/045901] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The structural evolution of Pb(Mg(1/3)Nb(2/3))O(3) (PMN) has been reviewed in terms of characteristic temperatures, length scales and timescales, with a view to considering the overall relaxor behaviour from the perspectives of strain and elasticity. A conventional analysis of lattice parameter data in terms of spontaneous strain and strain/order parameter coupling shows that even though a normal phase transition does not occur the relaxor ordering process is accompanied by a significant volume strain which follows the pattern of a static order parameter evolving according to that expected for a tricritical phase transition with T(c) ≈ 350 K. This matches the evolution of the intensity of the elastic central peak in neutron scattering spectra, and reflects the development of static (or quasistatic) polar nanoregions (PNRs) as if by a mean-field phase transition. Use of a Landau free energy expansion, which includes Γ4(-) order parameter components to describe ferroelectric contributions and an R1(+) order parameter to describe cation ordering together with their formal coupling with strain, then allows the pattern of elastic softening expected for a cubic → rhombohedral phase transition to be anticipated. The extent to which observed softening differs from this static mean-field pattern serves to highlight the additional roles of local heterogeneity and relaxation dynamics in determining the relaxor properties of PMN.
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Affiliation(s)
- M A Carpenter
- Department of Earth Sciences, University of Cambridge, Cambridge, UK
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30
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Carpenter MA, Bryson JFJ, Catalan G, Zhang SJ, Donnelly NJ. Elastic and anelastic relaxations in the relaxor ferroelectric Pb(Mg1/3Nb2/3)O3: II. Strain-order parameter coupling and dynamic softening mechanisms. J Phys Condens Matter 2012; 24:045902. [PMID: 22186067 DOI: 10.1088/0953-8984/24/4/045902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Elastic and anelastic behaviour of single crystal and ceramic samples of Pb(Mg(1/3)Nb(2/3))O(3) has been investigated at frequencies of ~0.1-1.2 MHz through the temperature interval 10-800 K by resonant ultrasound spectroscopy (RUS). Comparison with data from the literature shows that softening of the shear modulus between the Burns temperature and the freezing interval is independent of frequency. The softening is attributed to coupling between acoustic modes and the relaxation mode(s) responsible for central peaks in Raman and neutron scattering spectra below the Burns temperature, and can be described with Vogel-Fulcher parameters. Shear elastic compliance and dielectric permittivity show similar patterns of temperature dependence through the freezing interval, demonstrating strong coupling between ferroelectric polarization and strain such that the response to applied stress is more or less the same as the response to an applied electric field, with a frequency dependence consistent with Vogel-Fulcher-like freezing in both cases. Differences in detail show, however, that shearing induces flipping between different twin orientations, in comparison with the influence of an electric field, which induces 180° flipping: the activation energy barrier for the former appears to be higher than for the latter. Below the freezing interval, the anelastic loss also has a similar pattern of evolution to the dielectric loss, signifying again that essentially the same mechanism is involved in the freezing process. Overall softening at low temperatures is attributed to the contributions of strain relaxations due to coupling with the local ferroelectric order parameter and of coupling between acoustic modes and continuing relaxational modes of the polar nanostructure. Dissipation is attributed to movement of boundaries between PNRs or between correlated clusters of PNRs. Overall, strain coupling is fundamental to the development of the characteristic strain, dielectric and elastic properties of relaxors.
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Affiliation(s)
- M A Carpenter
- Department of Earth Sciences, University of Cambridge, Cambridge, UK
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31
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Catalan G, Lubk A, Vlooswijk AHG, Snoeck E, Magen C, Janssens A, Rispens G, Rijnders G, Blank DHA, Noheda B. Flexoelectric rotation of polarization in ferroelectric thin films. Nat Mater 2011; 10:963-967. [PMID: 22001961 DOI: 10.1038/nmat3141] [Citation(s) in RCA: 161] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Accepted: 09/08/2011] [Indexed: 05/31/2023]
Abstract
Strain engineering enables modification of the properties of thin films using the stress from the substrates on which they are grown. Strain may be relaxed, however, and this can also modify the properties thanks to the coupling between strain gradient and polarization known as flexoelectricity. Here we have studied the strain distribution inside epitaxial films of the archetypal ferroelectric PbTiO(3), where the mismatch with the substrate is relaxed through the formation of domains (twins). Synchrotron X-ray diffraction and high-resolution scanning transmission electron microscopy reveal an intricate strain distribution, with gradients in both the vertical and, unexpectedly, the horizontal direction. These gradients generate a horizontal flexoelectricity that forces the spontaneous polarization to rotate away from the normal. Polar rotations are a characteristic of compositionally engineered morphotropic phase boundary ferroelectrics with high piezoelectricity; flexoelectricity provides an alternative route for generating such rotations in standard ferroelectrics using purely physical means.
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Affiliation(s)
- G Catalan
- Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands.
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32
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Catalan G, Gómez R, Marchetti P, Vidal A, Castillo O. UP-03.121 Complications of Continent Catheterizable Channels: A 25-Year Experience. Urology 2011. [DOI: 10.1016/j.urology.2011.07.1210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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33
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Marchetti P, Gomez R, Catalan G, Vidal A, Castillo O. UP-03.123 What is the Best Technique for Primary Closure of the Bladder Neck in Continent Ileovesicostomy? Urology 2011. [DOI: 10.1016/j.urology.2011.07.1212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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34
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Martí X, Ferrer P, Herrero-Albillos J, Narvaez J, Holy V, Barrett N, Alexe M, Catalan G. Skin layer of BiFeO(3) single crystals. Phys Rev Lett 2011; 106:236101. [PMID: 21770522 DOI: 10.1103/physrevlett.106.236101] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Revised: 03/21/2011] [Indexed: 05/31/2023]
Abstract
A surface layer ("skin") different from the bulk was found in single crystals of BiFeO(3). Impedance analysis and grazing incidence x-ray diffraction reveal a phase transition at T(*)∼275±5 °C that is confined within the surface of BiFeO(3). X-ray photoelectron spectroscopy and refraction-corrected x-ray diffraction as a function of incidence angle and photon wavelength indicate a reduced electron density and an elongated out-of-plane lattice parameter within a few nanometers of the surface. The skin will affect samples with large surface to volume ratios, as well as devices that rely on interfacial coupling such as exchange bias.
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Affiliation(s)
- Xavi Martí
- Charles University in Prague, Faculty of Mathematics and Physics, Prague, Czech Republic.
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35
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Scherwitzl R, Zubko P, Lezama IG, Ono S, Morpurgo AF, Catalan G, Triscone JM. Electric-field control of the metal-insulator transition in ultrathin NdNiO₃ films. Adv Mater 2010; 22:5517-5520. [PMID: 20976681 DOI: 10.1002/adma.201003241] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
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36
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Gómez R, Marchetti P, Catalan G, Vidal A, Castillo O. POD-2.08: Bladder augmentation for hyperactive spinal cord neurogenic bladder: comparison of open versus laparoscopic ileocystoplasty. Urology 2010. [DOI: 10.1016/j.urology.2010.07.129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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37
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Herrero-Albillos J, Catalan G, Rodriguez-Velamazan JA, Viret M, Colson D, Scott JF. Neutron diffraction study of the BiFeO₃ spin cycloid at low temperature. J Phys Condens Matter 2010; 22:256001. [PMID: 21393809 DOI: 10.1088/0953-8984/22/25/256001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The reported observation of two anomalies in the intensity of the magnon Raman peaks of BiFeO₃ at 140 and 200 K (Singh et al 2008 J. Phys.: Condens. Mater 20 252203; Cazayous et al 2008 Phys. Rev. Lett. 101 037601) led to the hypothesis that such anomalies might originate from a spin reorientation transition. In order to test this hypothesis, we have used temperature-dependent neutron diffraction to track the evolution of the magnetic configuration in single crystals of BiFeO₃. Our results indicate that there is no average reorientation of the spins. This suggests that the magnon anomalies may instead be related to the freezing of modes that do not alter the average projection of the spins over the plane of the cycloid, as also reported for multiferroic TbMnO₃ (Senff et al 2006 J. Phys.: Condens. Mater 18 2069).
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Affiliation(s)
- Julia Herrero-Albillos
- Department of Materials Science, University of Cambridge, Pembroke Street, Cambridge, UK
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38
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Abstract
We present ab initio calculations of the longitudinal flexoelectricity for BaTiO(3) and SrTiO(3) using a direct approach. The calculated value for SrTiO(3) agrees with recently reported measurements. For BaTiO(3), however, the theoretical values are smaller than the measured ones; possible reasons for the discrepancy are discussed.
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Affiliation(s)
- Jiawang Hong
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, UK
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39
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Abstract
Almost free-standing single crystal mesoscale and nanoscale dots of ferroelectric BaTiO(3) have been made by direct focused ion beam patterning of bulk single crystal material. The domain structures which appear in these single crystal dots, after cooling through the Curie temperature, were observed to form into quadrants, with each quadrant consisting of fine 90 degrees stripe domains. The reason that these rather complex domain configurations form is uncertain, but we consider and discuss three possibilities for their genesis: first, that the quadrant features initially form to facilitate field-closure, but then develop 90 degrees shape compensating stripe domains in order to accommodate disclination stresses; second, that they are the result of the impingement of domain packets which nucleate at the sidewalls of the dots forming "Forsbergh" patterns (essentially the result of phase transition kinetics); and third, that 90 degrees domains form to conserve the shape of the nanodot as it is cooled through the Curie temperature but arrange into quadrant packets in order to minimize the energy associated with uncompensated surface charges (thus representing an equilibrium state). While the third model is the preferred one, we note that the second and third models are not mutually exclusive.
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Affiliation(s)
- A Schilling
- Centre for Nanostructured Media, School of Maths and Physics, Queen's University Belfast, Belfast BT7 1NN, UK
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40
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Daumont CJM, Mannix D, Venkatesan S, Catalan G, Rubi D, Kooi BJ, De Hosson JTM, Noheda B. Epitaxial TbMnO(3) thin films on SrTiO(3) substrates: a structural study. J Phys Condens Matter 2009; 21:182001. [PMID: 21825442 DOI: 10.1088/0953-8984/21/18/182001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
TbMnO(3) films have been grown under compressive strain on (001)-oriented SrTiO(3) crystals. They have an orthorhombic structure and display the (001) orientation. With increasing thickness, the structure evolves from a more symmetric (tetragonal) to a less symmetric (bulk-like orthorhombic) structure, while keeping constant the in-plane compression, thereby leaving the out-of-plane lattice spacing unchanged. The domain microstructure of the films is also revealed, showing an increasing number of orthorhombic domains as the thickness is decreased: we directly observe ferroelastic domains as narrow as 4 nm. The high density of domain walls may explain the induced ferromagnetism observed in the films, while both the decreased anisotropy and the small size of the domains could account for the absence of a ferroelectric spin spiral phase.
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Affiliation(s)
- C J M Daumont
- Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands
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41
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Seidel J, Martin LW, He Q, Zhan Q, Chu YH, Rother A, Hawkridge ME, Maksymovych P, Yu P, Gajek M, Balke N, Kalinin SV, Gemming S, Wang F, Catalan G, Scott JF, Spaldin NA, Orenstein J, Ramesh R. Conduction at domain walls in oxide multiferroics. Nat Mater 2009; 8:229-34. [PMID: 19169247 DOI: 10.1038/nmat2373] [Citation(s) in RCA: 392] [Impact Index Per Article: 26.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2008] [Accepted: 12/22/2008] [Indexed: 05/14/2023]
Abstract
Domain walls may play an important role in future electronic devices, given their small size as well as the fact that their location can be controlled. Here, we report the observation of room-temperature electronic conductivity at ferroelectric domain walls in the insulating multiferroic BiFeO(3). The origin and nature of the observed conductivity are probed using a combination of conductive atomic force microscopy, high-resolution transmission electron microscopy and first-principles density functional computations. Our analyses indicate that the conductivity correlates with structurally driven changes in both the electrostatic potential and the local electronic structure, which shows a decrease in the bandgap at the domain wall. Additionally, we demonstrate the potential for device applications of such conducting nanoscale features.
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Affiliation(s)
- J Seidel
- Department of Physics, University of California, Berkeley, 94720 California, USA.
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42
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Gomez R, Marchetti P, Catalan G. SCHU-40: Continent Reconstructive Surgery of the Neurogenic Bladder. Urology 2008. [DOI: 10.1016/j.urology.2008.08.048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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43
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Catalan G, Gomez R, Marchetti P. SCHU-23: Ostomy Problems with Catheterizable Continent Reservoirs. Urology 2008. [DOI: 10.1016/j.urology.2008.08.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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44
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Kawasaki S, Fan HJ, Catalan G, Morrison FD, Tatsuta T, Tsuji O, Scott JF. Solution-process coating of vertical ZnO nanowires with ferroelectrics. Nanotechnology 2008; 19:375302. [PMID: 21832546 DOI: 10.1088/0957-4484/19/37/375302] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We have developed a modified misted deposition process by combining substrate and mist heating for the deposition of ferroelectrics on 3D nanostructures. Arrays of vertical ZnO nanowires, sputter coated with Pd bottom electrodes, are used as the substrate. Scanning electron microscopy investigations show that conformal coating of ferroelectric Pb(Zr,Ti)O(3) (PZT) with good step coverage is obtained at deposition temperatures above 140 °C. The substrate heating also eliminates the common 'bundling' problem of the nanowire arrays. On the basis of data on x-ray diffraction, energy dispersive x-ray spectroscopy, and P-E hysteresis of PZT films on flat substrates, we obtain the optimum substrate temperature window to be 180-220 °C, in terms of best step coverage and an evident ferroelectricity. This is a significant step towards the end-goal of fully integrated ZnO nanowires with ferroelectric capacitors, which may be useful for the light-emitting applications of ZnO.
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Affiliation(s)
- Susumu Kawasaki
- Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, UK. SAMCO Incorporated, 36 Waraya-cho, Takeda, Fushimi-ku, Kyoto 612-8443, Japan
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45
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Catalan G, Béa H, Fusil S, Bibes M, Paruch P, Barthélémy A, Scott JF. Fractal dimension and size scaling of domains in thin films of multiferroic BiFeO3. Phys Rev Lett 2008; 100:027602. [PMID: 18232925 DOI: 10.1103/physrevlett.100.027602] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2007] [Indexed: 05/25/2023]
Abstract
Domains in ferroelectric films are usually smooth, stripelike, very thin compared with magnetic ones, and satisfy the Landau-Lifshitz-Kittel scaling law (width proportional to square root of film thickness). However, the ferroelectric domains in very thin films of multiferroic BiFeO3 have irregular domain walls characterized by a roughness exponent 0.5-0.6 and in-plane fractal Hausdorff dimension H||=1.4+/-0.1, and the domain size scales with an exponent 0.59+/-0.08 rather than 1/2. The domains are significantly larger than those of other ferroelectrics of the same thickness, and closer in size to those of magnetic materials, which is consistent with a strong magnetoelectric coupling at the walls. A general model is proposed for ferroelectrics, ferroelastics or ferromagnetic domains which relates the fractal dimension of the walls to domain size scaling.
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Affiliation(s)
- G Catalan
- Centre for Ferroics, Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, United Kingdom.
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46
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Zubko P, Catalan G, Buckley A, Welche PRL, Scott JF. Strain-gradient-induced polarization in SrTiO3 single crystals. Phys Rev Lett 2007; 99:167601. [PMID: 17995293 DOI: 10.1103/physrevlett.99.167601] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2007] [Indexed: 05/25/2023]
Abstract
Piezoelectricity is inherent only in noncentrosymmetric materials, but a piezoelectric response can also be obtained in centrosymmetric crystals if subjected to inhomogeneous deformation. This phenomenon, known as flexoelectricity, can significantly affect the functional properties of insulators, particularly thin films of high permittivity materials. We have measured strain-gradient-induced polarization in single crystals of paraelectric SrTiO3 as a function of temperature and orientation down to and below the 105 K phase transition. Estimates were obtained for all the components of the flexoelectric tensor, and calculations based on these indicate that local polarization around defects in SrTiO3 may exceed the largest ferroelectric polarizations. A sign reversal of the flexoelectric response detected below the phase transition suggests that the ferroelastic domain walls of SrTiO3 may be polar.
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Affiliation(s)
- P Zubko
- Centre for Ferroics, Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, United Kingdom.
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Abstract
Materials showing simultaneous ferroelectric and magnetic ordering are attracting a great deal of interest because of their unusual physics and potential applications. Hemberger et al. have reported relaxor-like dielectric properties and colossal magnetocapacitance (in excess of 500%) for the cubic spinel compound CdCr2S4 and related isomorphs, concluding that CdCr2S4 is a multiferroic relaxor. We argue here, however, that their results might also be explained by a conductive artefact.
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Affiliation(s)
- Gustau Catalan
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK.
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Catalan G, Janssens A, Rispens G, Csiszar S, Seeck O, Rijnders G, Blank DHA, Noheda B. Polar domains in lead titanate films under tensile strain. Phys Rev Lett 2006; 96:127602. [PMID: 16605960 DOI: 10.1103/physrevlett.96.127602] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2005] [Indexed: 05/08/2023]
Abstract
Thin films of PbTiO3, a classical ferroelectric, have been grown under tensile strain on single-crystal substrates of DyScO3. The films, of only 5 nm thickness, grow fully coherent with the substrate, as evidenced by synchrotron x-ray diffraction. A mapping of the reciprocal space reveals intensity modulations (satellites) due to regularly spaced polar domains in which the polarization appears rotated away from the substrate normal, characterizing a low-symmetry phase not observed in the bulk material. This could have important practical implications since these phases are known to be responsible for ultrahigh piezoelectric responses in complex systems.
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Affiliation(s)
- G Catalan
- Materials Science Centre, University of Groningen, Groningen 9747AG, The Netherlands.
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Ricci M, Elliott M, Cohen GA, Catalan G, Stark J, de Leval MR, Tsang VT. Management of pulmonary venous obstruction after correction of TAPVC: risk factors for adverse outcome. Eur J Cardiothorac Surg 2003; 24:28-36; discussion 36. [PMID: 12853042 DOI: 10.1016/s1010-7940(03)00180-5] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
OBJECTIVE Recurrent pulmonary venous obstruction (PVO) occurs in 0-18% of infants undergoing correction of total anomalous pulmonary venous connection (TAPVC). Limited published data suggest that PVO usually develops within 6 months of primary repair, and that outcomes of reoperations are poor. This study aimed to review our experience of reoperations for PVO post-TAPVC repair and to identify risk factors for adverse outcome. METHODS Twenty patients underwent reoperation for PVO between 1982 and 2002. Clinical data were reviewed. TAPVC was mostly infracardiac (11 patients). TAPVC was obstructed in nine patients. PVO developed early (<6 months) in seven patients, and late in 13 (>6 months). Time of presentation was unrelated to type of PVO (anastomotic vs. ostial). Repair was accomplished using various techniques (anastomotic enlargement with native atrial tissue, enlargement with pericardium, free or in situ, or other prosthetic material). Follow-up ranged from 1 month to 15 years (average 44 months). RESULTS Thirteen patients received one reoperation, while seven had multiple reoperations. In 13 patients, PVO was defined as new onset (no obstruction post-TAPVC repair), and in seven patients as residual (minimal obstructive changes post-TAPVC repair that progressed to PVO). Ten patients presented with anastomotic PVO, six with anastomotic and ostial PVO (involving the PVs), three with ostial PVO, and one with coronary sinus-left atrial junction stenosis. Mortality was 25% (5/20). Six of the ten patients with anastomotic PVO underwent one reoperation (2/6 died); the other four developed ostial PVO after reoperation, requiring multiple procedures (2/4 died). Mode of presentation (new onset vs. residual), site of obstruction (anastomotic vs. ostial), preoperative RV pressure (<0.8 vs. >0.8 systemic), number of reoperations (single vs. multiple), residual obstruction (presence or absence), and operative approach (Gore-tex or not) did not seem to affect outcomes. Risk factors for death were early presentation (<6 months) and persistence of pulmonary hypertension after reoperation; early presentation was also a risk factor for multiple reoperations. CONCLUSIONS Our findings support the conclusion that early presentation and postoperative pulmonary hypertension have the greatest adverse impact on outcome. Of these, failure to achieve a low-pressure pulmonary vascular system seems to be the variable that most strongly prevents survival. In our series, neither ostial PVO nor multiple re-interventions significantly increased surgical risk. The negative impact of postoperative residual obstruction on outcome was not striking. However, an aggressive surgical approach to this disease is still warranted. Although the role of each technique in obtaining long-lasting relief of PVO remains to be established, the use of artificial material seems unwise.
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Affiliation(s)
- M Ricci
- Cardiothoracic Unit, Great Ormond Street Hospital for Children NHS Trust, Great Ormond Street, London WC1N 3JH, UK
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