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Christensen DV, Steegemans TS, D Pomar T, Chen YZ, Smith A, Strocov VN, Kalisky B, Pryds N. Extreme magnetoresistance at high-mobility oxide heterointerfaces with dynamic defect tunability. Nat Commun 2024; 15:4249. [PMID: 38762504 PMCID: PMC11102559 DOI: 10.1038/s41467-024-48398-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 04/30/2024] [Indexed: 05/20/2024] Open
Abstract
Magnetic field-induced changes in the electrical resistance of materials reveal insights into the fundamental properties governing their electronic and magnetic behavior. Various classes of magnetoresistance have been realized, including giant, colossal, and extraordinary magnetoresistance, each with distinct physical origins. In recent years, extreme magnetoresistance (XMR) has been observed in topological and non-topological materials displaying a non-saturating magnetoresistance reaching 103-108% in magnetic fields up to 60 T. XMR is often intimately linked to a gapless band structure with steep bands and charge compensation. Here, we show that a linear XMR of 80,000% at 15 T and 2 K emerges at the high-mobility interface between the large band-gap oxides γ-Al2O3 and SrTiO3. Despite the chemically and electronically very dissimilar environment, the temperature/field phase diagrams of γ-Al2O3/SrTiO3 bear a striking resemblance to XMR semimetals. By comparing magnetotransport, microscopic current imaging, and momentum-resolved band structures, we conclude that the XMR in γ-Al2O3/SrTiO3 is not strongly linked to the band structure, but arises from weak disorder enforcing a squeezed guiding center motion of electrons. We also present a dynamic XMR self-enhancement through an autonomous redistribution of quasi-mobile oxygen vacancies. Our findings shed new light on XMR and introduce tunability using dynamic defect engineering.
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Affiliation(s)
- D V Christensen
- Department of Energy Conversion and Storage, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark.
| | - T S Steegemans
- Department of Energy Conversion and Storage, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark
| | - T D Pomar
- Department of Energy Conversion and Storage, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark
| | - Y Z Chen
- Department of Energy Conversion and Storage, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - A Smith
- Department of Energy Conversion and Storage, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark
| | - V N Strocov
- Swiss Light Source, Paul Scherrer Institute, 5232, Villigen-PSI, Switzerland
| | - B Kalisky
- Department of Physics and Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, 5290002, Israel
| | - N Pryds
- Department of Energy Conversion and Storage, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark
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2
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Christensen DV. Perspectives on oxide heterostructures - the curious case of γ-Al 2O 3/SrTiO 3. NANOSCALE 2023; 15:3704-3712. [PMID: 36723154 DOI: 10.1039/d2nr07172j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The heterostructure formed by depositing nanoscale thin films of spinel γ-Al2O3 on perovskite SrTiO3 exhibits a range of exciting properties including room temperature epitaxial growth, high electron mobility, strain-tunable magnetic order, and a symmetry-related reordering of the conduction bands. In comparison to the benchmark LaAlO3/SrTiO3 heterostructure, the γ-Al2O3/SrTiO3 heterostructure has been more sparsely investigated, which leaves plenty of room for scientific and technological discoveries. In this perspective article, I describe the key findings of the γ-Al2O3/SrTiO3 heterostructure and propose five directions for future research: (1) an exploration of novel phenomena emerging when relaxing the conventional epitaxial constraint of matching crystal structures across the interface, (2) a dynamic switching of a strong polarization through nanoscale electromigration of aluminum vacancies, (3) autonomous and forced enhancement of the electron mobility via oxygen vacancy diffusion, (4) writing and erasing of magnetic and conducting nanolines using ferroelastic domain walls, and (5) a multiferroic state formed by combining ferroelectricity, ferromagnetism, and ferroelasticity. The proposed research directions may shed light on both fundamental aspects of the heterostructure and pave the way for applications within green energy devices and nanoelectronics.
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3
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Popescu DG, Husanu MA, Constantinou PC, Filip LD, Trupina L, Bucur CI, Pasuk I, Chirila C, Hrib LM, Stancu V, Pintilie L, Schmitt T, Teodorescu CM, Strocov VN. Experimental Band Structure of Pb(Zr,Ti)O 3 : Mechanism of Ferroelectric Stabilization. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2205476. [PMID: 36592417 PMCID: PMC9951575 DOI: 10.1002/advs.202205476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 12/07/2022] [Indexed: 06/17/2023]
Abstract
Pb(Zr,Ti)O3 (PZT) is the most common ferroelectric (FE) material widely used in solid-state technology. Despite intense studies of PZT over decades, its intrinsic band structure, electron energy depending on 3D momentum k, is still unknown. Here, Pb(Zr0.2 Ti0.8 )O3 using soft-X-ray angle-resolved photoelectron spectroscopy (ARPES) is explored. The enhanced photoelectron escape depth in this photon energy range allows sharp intrinsic definition of the out-of-plane momentum k and thereby of the full 3D band structure. Furthermore, the problem of sample charging due to the inherently insulating nature of PZT is solved by using thin-film PZT samples, where a thickness-induced self-doping results in their heavy doping. For the first time, the soft-X-ray ARPES experiments deliver the intrinsic 3D band structure of PZT as well as the FE-polarization dependent electrostatic potential profile across the PZT film deposited on SrTiO3 and Lax SrMn1- x O3 substrates. The negative charges near the surface, required to stabilize the FE state pointing away from the sample (P+), are identified as oxygen vacancies creating localized in-gap states below the Fermi energy. For the opposite polarization state (P-), the positive charges near the surface are identified as cation vacancies resulting from non-ideal stoichiometry of the PZT film as deduced from quantitative XPS measurements.
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Affiliation(s)
| | | | | | - Lucian Dragos Filip
- National Institute of Materials PhysicsAtomistilor 405AMagurele077125Romania
| | - Lucian Trupina
- National Institute of Materials PhysicsAtomistilor 405AMagurele077125Romania
| | | | - Iuliana Pasuk
- National Institute of Materials PhysicsAtomistilor 405AMagurele077125Romania
| | - Cristina Chirila
- National Institute of Materials PhysicsAtomistilor 405AMagurele077125Romania
| | | | - Viorica Stancu
- National Institute of Materials PhysicsAtomistilor 405AMagurele077125Romania
| | - Lucian Pintilie
- National Institute of Materials PhysicsAtomistilor 405AMagurele077125Romania
| | - Thorsten Schmitt
- Swiss Light SourcePaul Scherrer InstituteVilligen‐PSI5232Switzerland
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Varotto S, Johansson A, Göbel B, Vicente-Arche LM, Mallik S, Bréhin J, Salazar R, Bertran F, Fèvre PL, Bergeal N, Rault J, Mertig I, Bibes M. Direct visualization of Rashba-split bands and spin/orbital-charge interconversion at KTaO 3 interfaces. Nat Commun 2022; 13:6165. [PMID: 36257940 PMCID: PMC9579156 DOI: 10.1038/s41467-022-33621-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 09/23/2022] [Indexed: 11/25/2022] Open
Abstract
Rashba interfaces have emerged as promising platforms for spin-charge interconversion through the direct and inverse Edelstein effects. Notably, oxide-based two-dimensional electron gases display a large and gate-tunable conversion efficiency, as determined by transport measurements. However, a direct visualization of the Rashba-split bands in oxide two-dimensional electron gases is lacking, which hampers an advanced understanding of their rich spin-orbit physics. Here, we investigate KTaO3 two-dimensional electron gases and evidence their Rashba-split bands using angle resolved photoemission spectroscopy. Fitting the bands with a tight-binding Hamiltonian, we extract the effective Rashba coefficient and bring insight into the complex multiorbital nature of the band structure. Our calculations reveal unconventional spin and orbital textures, showing compensation effects from quasi-degenerate band pairs which strongly depend on in-plane anisotropy. We compute the band-resolved spin and orbital Edelstein effects, and predict interconversion efficiencies exceeding those of other oxide two-dimensional electron gases. Finally, we suggest design rules for Rashba systems to optimize spin-charge interconversion performance. Visualization of the Rashbasplit bands in oxide two-dimensional electron gases is lacking, which hampers understanding of their rich spin-orbit physics. Here, the authors investigate KTaO3 two dimensional electron gases and their Rashba-split bands.
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Affiliation(s)
- Sara Varotto
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - Annika Johansson
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle, Germany.
| | - Börge Göbel
- Institute of Physics, Martin-Luther-Universität Halle-Wittenberg, 06099, Halle, Germany
| | - Luis M Vicente-Arche
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - Srijani Mallik
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - Julien Bréhin
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - Raphaël Salazar
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, Gif-sur-Yvette Cedex, 91192, France
| | - François Bertran
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, Gif-sur-Yvette Cedex, 91192, France
| | - Patrick Le Fèvre
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, Gif-sur-Yvette Cedex, 91192, France
| | - Nicolas Bergeal
- Laboratoire de Physique et d'Etude des Matériaux, ESPCI Paris, Université PSL, CNRS, 75005, Paris, France
| | - Julien Rault
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, Gif-sur-Yvette Cedex, 91192, France
| | - Ingrid Mertig
- Institute of Physics, Martin-Luther-Universität Halle-Wittenberg, 06099, Halle, Germany
| | - Manuel Bibes
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France.
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Li H, Gan Y, Husanu MA, Dahm RT, Christensen DV, Radovic M, Sun J, Shi M, Shen B, Pryds N, Chen Y. Robust Electronic Structure of Manganite-Buffered Oxide Interfaces with Extreme Mobility Enhancement. ACS NANO 2022; 16:6437-6443. [PMID: 35312282 DOI: 10.1021/acsnano.2c00609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The electronic structure as well as the mechanism underlying the high-mobility two-dimensional electron gases (2DEGs) at complex oxide interfaces remain elusive. Herein, using soft X-ray angle-resolved photoemission spectroscopy (ARPES), we present the band dispersion of metallic states at buffered LaAlO3/SrTiO3 (LAO/STO) heterointerfaces where a single-unit-cell LaMnO3 (LMO) spacer not only enhances the electron mobility but also renders the electronic structure robust toward X-ray radiation. By tracing the evolution of band dispersion, orbital occupation, and electron-phonon interaction of the interfacial 2DEG, we find unambiguous evidence that the insertion of the LMO buffer strongly suppresses both the formation of oxygen vacancies as well as the electron-phonon interaction on the STO side. The latter effect makes the buffered sample different from any other STO-based interfaces and may explain the maximum mobility enhancement achieved at buffered oxide interfaces.
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Affiliation(s)
- Hang Li
- Department of Energy Conversion and Storage, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen, PSI, Switzerland
| | - Yulin Gan
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, 100190 Beijing, China
| | - Marius-Adrian Husanu
- National Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, Romania
| | - Rasmus Tindal Dahm
- Department of Energy Conversion and Storage, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | | | - Milan Radovic
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen, PSI, Switzerland
| | - Jirong Sun
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, 100190 Beijing, China
| | - Ming Shi
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen, PSI, Switzerland
| | - Baogen Shen
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, 100190 Beijing, China
| | - Nini Pryds
- Department of Energy Conversion and Storage, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Yunzhong Chen
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, 100190 Beijing, China
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6
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Niu W, Fang YW, Liu R, Wu Z, Chen Y, Gan Y, Zhang X, Zhu C, Wang L, Xu Y, Pu Y, Chen Y, Wang X. Fully Optical Modulation of the Two-Dimensional Electron Gas at the γ-Al 2O 3/SrTiO 3 Interface. J Phys Chem Lett 2022; 13:2976-2985. [PMID: 35343699 DOI: 10.1021/acs.jpclett.2c00384] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Two-dimensional electron gas (2DEG) formed at the heterointerface between two oxide insulators hosts plenty of emergent phenomena and provides new opportunities for electronics and photoelectronics. However, despite being long sought after, on-demand properties controlled through a fully optical illumination remain far from being explored. Herein, a giant tunability of the 2DEG at the interface of γ-Al2O3/SrTiO3 through a fully optical gating is discovered. Specifically, photon-generated carriers lead to a delicate tunability of the carrier density and the underlying electronic structure, which is accompanied by the remarkable Lifshitz transition. Moreover, the 2DEG can be optically tuned to possess a maximum Rashba spin-orbit coupling, particularly at the crossing region of the sub-bands with different symmetries. First-principles calculations essentially well explain the optical modulation of γ-Al2O3/SrTiO3. Our fully optical gating opens a new pathway for manipulating emergent properties of the 2DEGs and is promising for on-demand photoelectric devices.
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Affiliation(s)
- Wei Niu
- New Energy Technology Engineering Laboratory of Jiangsu Province and School of Science, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, P. R. China
| | - Yue-Wen Fang
- Laboratory for Materials and Structures and Tokyo Tech World Research Hub Initiative (WRHI), Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, Kanagawa 226-8503, Japan
- NYU-ECNU Institute of Physics, New York University Shanghai, Shanghai 200122, China
| | - Ruxin Liu
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, P. R. China
| | - Zhenqi Wu
- New Energy Technology Engineering Laboratory of Jiangsu Province and School of Science, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
| | - Yongda Chen
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, P. R. China
| | - Yulin Gan
- Beijing National Laboratory for Condensed Matter and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xiaoqian Zhang
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Chunhui Zhu
- College of Physics, Hebei Normal University, Shijiazhuang 050024, China
| | - Lixia Wang
- New Energy Technology Engineering Laboratory of Jiangsu Province and School of Science, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
| | - Yongbing Xu
- New Energy Technology Engineering Laboratory of Jiangsu Province and School of Science, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, P. R. China
| | - Yong Pu
- New Energy Technology Engineering Laboratory of Jiangsu Province and School of Science, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
| | - Yunzhong Chen
- Beijing National Laboratory for Condensed Matter and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xuefeng Wang
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, P. R. China
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7
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Leermakers I, Rubi K, Yang M, Kerdi B, Goiran M, Escoffier W, Rana AS, Smink AEM, Brinkman A, Hilgenkamp H, Maan JC, Zeitler U. Quantum oscillations in an optically-illuminated two-dimensional electron system at the LaAlO 3/SrTiO 3interface. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:465002. [PMID: 34433152 DOI: 10.1088/1361-648x/ac211a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 08/25/2021] [Indexed: 06/13/2023]
Abstract
We have investigated the illumination effect on the magnetotransport properties of a two-dimensional electron system at the LaAlO3/SrTiO3interface. The illumination significantly reduces the zero-field sheet resistance, eliminates the Kondo effect at low-temperature, and switches the negative magnetoresistance into the positive one. A large increase in the density of high-mobility carriers after illumination leads to quantum oscillations in the magnetoresistance originating from the Landau quantization. The carrier density (∼2 × 1012 cm-2) and effective mass (∼1.7me) estimated from the oscillations suggest that the high-mobility electrons occupy thedxz/yzsubbands of Ti:t2gorbital extending deep within the conducting sheet of SrTiO3. Our results demonstrate that the illumination which induces additional carriers at the interface can pave the way to control the Kondo-like scattering and study the quantum transport in the complex oxide heterostructures.
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Affiliation(s)
- I Leermakers
- High Field Magnet Laboratory (HFML-EMFL) and Institute for Molecules and Materials, Radboud University, Nijmegen, The Netherlands
| | - K Rubi
- High Field Magnet Laboratory (HFML-EMFL) and Institute for Molecules and Materials, Radboud University, Nijmegen, The Netherlands
| | - M Yang
- Laboratoire National des Champs Magnétiques Intenses (LNCMI-EMFL), Université de Toulouse, CNRS, INSA, UPS, 143 Avenue de Rangueil, 31400 Toulouse, France
| | - B Kerdi
- Laboratoire National des Champs Magnétiques Intenses (LNCMI-EMFL), Université de Toulouse, CNRS, INSA, UPS, 143 Avenue de Rangueil, 31400 Toulouse, France
| | - M Goiran
- Laboratoire National des Champs Magnétiques Intenses (LNCMI-EMFL), Université de Toulouse, CNRS, INSA, UPS, 143 Avenue de Rangueil, 31400 Toulouse, France
| | - W Escoffier
- Laboratoire National des Champs Magnétiques Intenses (LNCMI-EMFL), Université de Toulouse, CNRS, INSA, UPS, 143 Avenue de Rangueil, 31400 Toulouse, France
| | - A S Rana
- MESA + Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
| | - A E M Smink
- MESA + Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
| | - A Brinkman
- MESA + Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
| | - H Hilgenkamp
- MESA + Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
| | - J C Maan
- High Field Magnet Laboratory (HFML-EMFL) and Institute for Molecules and Materials, Radboud University, Nijmegen, The Netherlands
| | - U Zeitler
- High Field Magnet Laboratory (HFML-EMFL) and Institute for Molecules and Materials, Radboud University, Nijmegen, The Netherlands
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