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Di Castro D, Cantoni C, Ridolfi F, Aruta C, Tebano A, Yang N, Balestrino G. High-T(c) Superconductivity at the Interface between the CaCuO2 and SrTiO3 Insulating Oxides. Phys Rev Lett 2015; 115:147001. [PMID: 26551817 DOI: 10.1103/physrevlett.115.147001] [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] [Received: 02/06/2015] [Indexed: 06/05/2023]
Abstract
At interfaces between complex oxides it is possible to generate electronic systems with unusual electronic properties, which are not present in the isolated oxides. One important example is the appearance of superconductivity at the interface between insulating oxides, although, until now, with very low T(c). We report the occurrence of high T(c) superconductivity in the bilayer CaCuO(2)/SrTiO(3), where both the constituent oxides are insulating. In order to obtain a superconducting state, the CaCuO(2)/SrTiO(3) interface must be realized between the Ca plane of CaCuO(2) and the TiO(2) plane of SrTiO(3). Only in this case can oxygen ions be incorporated in the interface Ca plane, acting as apical oxygen for Cu and providing holes to the CuO(2) planes. A detailed hole doping spatial profile can be obtained by scanning transmission electron microscopy and electron-energy-loss spectroscopy at the O K edge, clearly showing that the (super)conductivity is confined to about 1-2 CaCuO(2) unit cells close to the interface with SrTiO(3). The results obtained for the CaCuO(2)/SrTiO(3) interface can be extended to multilayered high T(c) cuprates, contributing to explaining the dependence of T(c) on the number of CuO(2) planes in these systems.
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Affiliation(s)
- D Di Castro
- Dipartimento di Ingegneria Civile e Ingegneria Informatica, Università di Roma Tor Vergata, Via del Politecnico 1, I-00133 Roma, Italy
- CNR-SPIN, Università di Roma Tor Vergata, Roma I-00133, Italy
| | - C Cantoni
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6116, USA
| | - F Ridolfi
- Dipartimento di Ingegneria Civile e Ingegneria Informatica, Università di Roma Tor Vergata, Via del Politecnico 1, I-00133 Roma, Italy
| | - C Aruta
- CNR-SPIN, Università di Roma Tor Vergata, Roma I-00133, Italy
| | - A Tebano
- Dipartimento di Ingegneria Civile e Ingegneria Informatica, Università di Roma Tor Vergata, Via del Politecnico 1, I-00133 Roma, Italy
- CNR-SPIN, Università di Roma Tor Vergata, Roma I-00133, Italy
| | - N Yang
- CNR-SPIN, Università di Roma Tor Vergata, Roma I-00133, Italy
- Facoltà di Ingegneria, Università degli studi Niccolò Cusano, Rome I-00166, Italy
| | - G Balestrino
- Dipartimento di Ingegneria Civile e Ingegneria Informatica, Università di Roma Tor Vergata, Via del Politecnico 1, I-00133 Roma, Italy
- CNR-SPIN, Università di Roma Tor Vergata, Roma I-00133, Italy
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Salvato M, Ottaviani I, Lucci M, Cirillo M, Di Castro D, Innocenti D, Tebano A, Balestrino G. Superconducting anisotropy in (CaCuO2)n/(SrTiO3)m superlattices. J Phys Condens Matter 2013; 25:335702. [PMID: 23883741 DOI: 10.1088/0953-8984/25/33/335702] [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: 06/02/2023]
Abstract
The superconducting properties of (CaCuO2)n/(SrTiO3)m artificial superlattices have been investigated via transport measurements under the application of external magnetic fields. The coherence lengths in the plane of the substrate and in the direction perpendicular to it (ξab and ξc, respectively) have been measured while varying m, the thickness of the SrTiO3 block. The results show that with increasing m, i.e. with increasing structural anisotropy, the superconducting anisotropy γ = ξab/ξc decreases. This apparent anomalous relation between the structural and the superconducting anisotropies suggests that γ is more affected by local doping at the interface rather than by the separation between the superconducting blocks. This interpretation of the experimental results has been confirmed by both the irreversibility lines and the magnetic field dependence of the activation energy for fluxon motion.
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Affiliation(s)
- M Salvato
- Dipartimento di Fisica and MINAS LAB, Università di Roma Tor Vergata, I-00133 Roma, Italy. CNR-SPIN, Italy
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Braicovich L, Ament LJP, Bisogni V, Forte F, Aruta C, Balestrino G, Brookes NB, De Luca GM, Medaglia PG, Granozio FM, Radovic M, Salluzzo M, van den Brink J, Ghiringhelli G. Dispersion of magnetic excitations in the cuprate La2CuO4 and CaCuO2 compounds measured using resonant x-ray scattering. Phys Rev Lett 2009; 102:167401. [PMID: 19518752 DOI: 10.1103/physrevlett.102.167401] [Citation(s) in RCA: 20] [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: 09/22/2008] [Indexed: 05/27/2023]
Abstract
By resonant inelastic x-ray scattering in the soft x-ray regime we probe the dynamical multiple-spin correlations in the antiferromagnetic cuprates La2CuO4 and CaCuO2. High resolution measurements at the copper L3 edge allow the clear observation of dispersing bimagnon excitations. Theory based on the ultrashort core-hole lifetime expansion fits the data on these coherent spin excitations without free parameters.
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Affiliation(s)
- L Braicovich
- CNR-INFM Coherentia and Soft, Dipartimento di Fisica, Politecnico di Milano, I-20133 Milano, Italy
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Tebano A, Aruta C, Sanna S, Medaglia PG, Balestrino G, Sidorenko AA, De Renzi R, Ghiringhelli G, Braicovich L, Bisogni V, Brookes NB. Evidence of orbital reconstruction at interfaces in ultrathin La0.67Sr0.33MnO3 films. Phys Rev Lett 2008; 100:137401. [PMID: 18517994 DOI: 10.1103/physrevlett.100.137401] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2007] [Indexed: 05/26/2023]
Abstract
Linear dichroism (LD) in x-ray absorption, diffraction, transport, and magnetization measurements on thin La(0.7)Sr(0.3)MnO(3) films grown on different substrates, allow identification of a peculiar interface effect, related just to the presence of the interface. We report the LD signature of preferential 3d-e(g)(3z(2)-r(2)) occupation at the interface, suppressing the double exchange mechanism. This surface orbital reconstruction is opposite to that favored by residual strain and is independent of dipolar fields, the chemical nature of the substrate and the presence of capping layers.
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Affiliation(s)
- A Tebano
- CNR-INFM Coherentia and Dipartimento di Ingegneria Meccanica, Università di Roma Tor Vergata, Via del Politecnico 1, 00133 Roma, Italy
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Orgiani P, Aruta C, Balestrino G, Born D, Maritato L, Medaglia PG, Stornaiuolo D, Tafuri F, Tebano A. Direct measurement of sheet resistance Rsquare in cuprate systems: evidence of a fermionic scenario in a metal-insulator transition. Phys Rev Lett 2007; 98:036401. [PMID: 17358700 DOI: 10.1103/physrevlett.98.036401] [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] [Received: 10/25/2006] [Indexed: 05/14/2023]
Abstract
The metal-insulator transition (MIT) has been studied in Ba(0.9)Nd(0.1)CuO(2+x)/CaCuO2 ultrathin cuprate structures. Such structures allow for the direct measurement of the 2D sheet resistance R( square), eliminating ambiguity in the definition of the effective thickness of the conducting layer in high temperature superconductors. The MIT occurs at room temperature for experimental values of R(square) close to the 25.8 kOmega universal quantum resistance. All data confirm the assumption that each CaCuO2 layer forms a 2D superconducting sheet within the superconducting block, which can be described as weak-coupled equivalent sheets in parallel.
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Affiliation(s)
- P Orgiani
- CNR-INFM Supermat and Department of Physics, University of Salerno, Baronissi (SA), Italy
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Freelon B, Augustsson A, Guo JH, Medaglia PG, Tebano A, Balestrino G. Electron correlation and charge transfer in superconducting superlattices. Phys Rev Lett 2006; 96:017003. [PMID: 16486500 DOI: 10.1103/physrevlett.96.017003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2004] [Indexed: 05/06/2023]
Abstract
We use x-ray spectroscopy to examine the electronic structure of high-temperature superconducting superlattices [(Ba0.9Nd0.10)CuO(2 + delta)]2/[CaCuO2]2. The O 2p density of states reveals the insulating character of the individual component layers and the metallic character of the superlattices. We report the first direct observation of Zhang-Rice singlets in artificial high-temperature superconducting heteroepitaxial structures. The experimental findings in the superlattices and its component layers offer evidence of charge transport from the so-called charge reservoir layer to the superconducting infinite layer. This suggests a strong link between superconductivity and both electron correlation and charge transfer within the superlattices.
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Affiliation(s)
- B Freelon
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
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Tafuri F, Kirtley JR, Medaglia PG, Orgiani P, Balestrino G. Magnetic imaging of pearl vortices in artificially layered (Ba0.9Nd0.1CuO2+x)m/(CaCuO2)n systems. Phys Rev Lett 2004; 92:157006. [PMID: 15169312 DOI: 10.1103/physrevlett.92.157006] [Citation(s) in RCA: 4] [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] [Received: 06/17/2003] [Indexed: 05/24/2023]
Abstract
We have used scanning SQUID magnetometry to image vortices in ultrathin (Ba0.9Nd0.1CuO2+x)(m)/(CaCuO2)(n) high temperature superconductor samples, with as few as three superconducting CuO2 planes. The Pearl lengths (Lambda=2lambda(2)(L)/d, lambda(L) the London penetration depth, d the superconducting film thickness) in these samples, as determined by fits to the vortex images, agree with those by local susceptibility measurements, and can be as long as 1 mm. The in-plane penetration depths lambda(ab) inferred from the Pearl lengths are longer than many bulk cuprates with comparable critical temperatures. We speculate on the causes of the long penetration depths, and on the possibility of exploiting the unique properties of these superconductors for basic experiments.
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Affiliation(s)
- F Tafuri
- INFM-Coherentia, Dipartimento di Ingegneria dell'Informazione, Seconda Università di Napoli, Aversa (CE), Italy
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Balestrino G, Medaglia PG, Orgiani P, Tebano A, Aruta C, Lavanga S, Varlamov AA. Very large purely intralayer critical current density in ultrathin cuprate artificial structures. Phys Rev Lett 2002; 89:156402. [PMID: 12366006 DOI: 10.1103/physrevlett.89.156402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2002] [Indexed: 05/23/2023]
Abstract
Ultrathin artificial high temperature superconducting structures, consisting of (Ba(0.9)Nd0.1)CuO2+x and CaCuO2 layers, were grown by pulsed laser deposition. Intralayer superconductivity at 60 K was obtained for a structure consisting of a single (CaCuO2) block sandwiched between two (Ba(0.9)Nd0.1)CuO2+x charge reservoir blocks. The purely intralayer critical current density was measured at 4.2 K and resulted to be larger than 10(8) A/cm(2). These findings clearly show that interaction between nearest neighbor (CaCuO2) layers is not essential for high T(c) superconductivity and strongly supports the physical model based on the idea that intralayer interaction alone is responsible for high temperature superconductivity.
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Affiliation(s)
- G Balestrino
- INFM-COHERENTIA and Dipartimento di Ingegneria Meccanica, Università di Roma Tor Vergata, Via del Politecnico 1, Italy
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Aruta C, Zegenhagen J, Cowie B, Balestrino G, Pasquini G, Medaglia P, Ricci F, Luebbert D, Baumbach T, Riedo E, Ortega L, Kremer R, Albrecht J. Structure of Superconducting [BaCuOx]2/[CaCuO2]n Superlattices on SrTiO3(001) Investigated by X-ray Scattering. ACTA ACUST UNITED AC 2001. [DOI: 10.1002/1521-396x(200102)183:2<353::aid-pssa353>3.0.co;2-v] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Balestrino G, Milani E, Aruta C, Varlamov AA. c-axis resistance peak above the critical temperature in layered superconductors. Phys Rev B Condens Matter 1996; 54:3628-3632. [PMID: 9986270 DOI: 10.1103/physrevb.54.3628] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Nygmatulin AS, Varlamov AA, Livanov DV, Balestrino G, Milani E. Effect of the magnetic field on the c-axis resistance peak in Bi2Sr2CaCu2O8+x epitaxial films. Phys Rev B Condens Matter 1996; 53:3557-3560. [PMID: 9983870 DOI: 10.1103/physrevb.53.3557] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Balestrino G, Crisan A, Livanov DV, Milani E, Montuori M, Varlamov AA. Two-dimensional vortex and phase fluctuations from current-voltage characteristics of Bi2Sr2CaCu2O8+x films with various oxygen contents. Phys Rev B Condens Matter 1995; 51:9100-9106. [PMID: 9977550 DOI: 10.1103/physrevb.51.9100] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Balestrino G, Livanov DV, Milani E, Camarota B, Fiorani D, Testa AM. Vortex-lattice melting in Bi2Sr2CaCu2O8+ delta epitaxial films: Role of the oxygen stoichiometry. Phys Rev B Condens Matter 1994; 50:3446-3449. [PMID: 9976608 DOI: 10.1103/physrevb.50.3446] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Epifani M, Mancino P, Balestrino G, Marinelli M, Milani E, Montuori M, Ruosi A, Vaglio R. Composite bolometer based on high temperature superconducting Bi2Sr2CaCu2O8+x crystals for application in the far infrared. ACTA ACUST UNITED AC 1994. [DOI: 10.1051/jp4:1994640] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Balestrino G, Marinelli M, Milani E, Varlamov AA, Yu L. Experimental evidence in favor of the fluctuation origin of the transverse-resistance increase near the edge of the superconducting transition in Bi2Sr2CaCu2O8+ delta. Phys Rev B Condens Matter 1993; 47:6037-6042. [PMID: 10004551 DOI: 10.1103/physrevb.47.6037] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Balestrino G, Marinelli M, Milani E, Reggiani L, Vaglio R, Varlamov AA. Excess conductivity in 2:2:1:2-phase Bi-Sr-Ca-Cu-O epitaxial thin films. Phys Rev B Condens Matter 1992; 46:14919-14921. [PMID: 10003600 DOI: 10.1103/physrevb.46.14919] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Silva E, Giura M, Marcon R, Fastampa R, Balestrino G, Marinelli M, Milani E. Magnetic-field-induced microwave losses in epitaxial Bi-Sr-Ca-Cu-O films. Phys Rev B Condens Matter 1992; 45:12566-12572. [PMID: 10001298 DOI: 10.1103/physrevb.45.12566] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Balzarotti A, Motta N, Patella F, Sgarlata A, Paroli P, Balestrino G, Marinelli M. X-ray-photoemission-spectroscopy study of the surface deterioration of Bi2Sr2CaCu2O8 and Bi1.7Pb0.3Sr2CaCu2O8 single crystals at 26 K. Phys Rev B Condens Matter 1991; 43:11500-11503. [PMID: 9996912 DOI: 10.1103/physrevb.43.11500] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Balestrino G, Nigro A, Vaglio R, Marinelli M. Thermodynamic fluctuations in the 110-K Bi-Sr-Ca-Cu-O superconductor: Evidence for two-dimensional behavior. Phys Rev B Condens Matter 1989; 39:12264-12266. [PMID: 9948063 DOI: 10.1103/physrevb.39.12264] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Karim R, Oliver SA, Vittoria C, Widom A, Balestrino G, Barbanera S, Paroli P. Low-field dependence of the microwave absorption in superconducting YBa2Cu3O7-x near Tc. Phys Rev B Condens Matter 1989; 39:797-800. [PMID: 9947235 DOI: 10.1103/physrevb.39.797] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Balestrino G, Barbanera S, Paoletti A, Paroli P, Antisari MV. Superstructure along the c axis in YBa2Cu3O7-x single crystals having Tc=92 K. Phys Rev B Condens Matter 1988; 38:6609-6613. [PMID: 9945336 DOI: 10.1103/physrevb.38.6609] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
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Bartucci R, Colavita E, Sportelli L, Balestrino G, Barbanera S. Electron paramagnetic resonance of single-phase pellets of the high-Tc superconductor YBa2Cu. Phys Rev B Condens Matter 1988; 37:2313-2316. [PMID: 9944762 DOI: 10.1103/physrevb.37.2313] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
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Balestrino G, Paroli P, Geller S. Growth anisotropy in the Nd-Y and Pr-Y iron garnets. Phys Rev B Condens Matter 1986; 34:8104-8106. [PMID: 9939499 DOI: 10.1103/physrevb.34.8104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
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