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Haselmann U, Suyolcu YE, Wu PC, Ivanov YP, Knez D, van Aken PA, Chu YH, Zhang Z. Negatively Charged In-Plane and Out-Of-Plane Domain Walls with Oxygen-Vacancy Agglomerations in a Ca-Doped Bismuth-Ferrite Thin Film. ACS APPLIED ELECTRONIC MATERIALS 2021; 3:4498-4508. [PMID: 34723187 PMCID: PMC8552442 DOI: 10.1021/acsaelm.1c00638] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 09/12/2021] [Indexed: 06/13/2023]
Abstract
The interaction of oxygen vacancies and ferroelectric domain walls is of great scientific interest because it leads to different domain-structure behaviors. Here, we use high-resolution scanning transmission electron microscopy to study the ferroelectric domain structure and oxygen-vacancy ordering in a compressively strained Bi0.9Ca0.1FeO3-δ thin film. It was found that atomic plates, in which agglomerated oxygen vacancies are ordered, appear without any periodicity between the plates in out-of-plane and in-plane orientation. The oxygen non-stoichiometry with δ ≈ 1 in FeO2-δ planes is identical in both orientations and shows no preference. Within the plates, the oxygen vacancies form 1D channels in a pseudocubic [010] direction with a high number of vacancies that alternate with oxygen columns with few vacancies. These plates of oxygen vacancies always coincide with charged domain walls in a tail-to-tail configuration. Defects such as ordered oxygen vacancies are thereby known to lead to a pinning effect of the ferroelectric domain walls (causing application-critical aspects, such as fatigue mechanisms and countering of retention failure) and to have a critical influence on the domain-wall conductivity. Thus, intentional oxygen vacancy defect engineering could be useful for the design of multiferroic devices with advanced functionality.
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Affiliation(s)
- Ulrich Haselmann
- Erich
Schmid Institute of Materials Science, Austrian
Academy of Sciences, Leoben 8700, Austria
| | - Y. Eren Suyolcu
- Department
of Materials Science and Engineering, Cornell
University, Ithaca, New York 14850, United States
- Max
Planck Institute for Solid State Research, 70569 Stuttgart, Germany
| | - Ping-Chun Wu
- Department
of Materials Science and Engineering, National
Chiao Tung University, Hsinchu 30010, Taiwan
| | - Yurii P. Ivanov
- Erich
Schmid Institute of Materials Science, Austrian
Academy of Sciences, Leoben 8700, Austria
- Department
of Materials Science & Metallurgy, University
of Cambridge, Cambridge CB3 0FS, U.K.
- School of
Natural Sciences, Far Eastern Federal University, Vladivostok 690950, Russia
| | - Daniel Knez
- Graz
Centre for Electron Microscopy, Austrian
Cooperative Research, Graz 8010, Austria
| | - Peter A. van Aken
- Max
Planck Institute for Solid State Research, 70569 Stuttgart, Germany
| | - Ying-Hao Chu
- Department
of Materials Science and Engineering, National
Chiao Tung University, Hsinchu 30010, Taiwan
| | - Zaoli Zhang
- Erich
Schmid Institute of Materials Science, Austrian
Academy of Sciences, Leoben 8700, Austria
- Institute
of Material Physics, Montanuniversität
Leoben, Leoben 8700, Austria
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2
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Quantitative in Situ X-ray Diffraction Analysis of Early Hydration of Belite-Calcium Sulfoaluminate Cement at Various Defined Temperatures. MINERALS 2021. [DOI: 10.3390/min11030297] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The influence of temperature on the early hydration of belite-calcium sulfoaluminate cements with two different calcium sulfate to calcium sulfoaluminate molar ratios was investigated. The phase composition and phase assemblage development of cements prepared using molar ratios of 1 and 2.5 were studied at 25, 40 and 60 °C by in situ X-ray powder diffraction. The Rietveld refinement method was used for quantification. The degree of hydration after 24 h was highest at ambient temperatures, but early hydration was significantly accelerated at elevated temperatures. These differences were more noticeable when we increased the temperature from 25 °C to 40 °C, than it was increased from 40 °C to 60 °C. The amount of calcium sulfate added controls the amount of the precipitated ettringite, namely, the amount of ettringite increased in the cement with a higher molar ratio. The results showed that temperature also affects full width at half maximum of ettringite peaks, which indicates a decrease in crystallite size of ettringite at elevated temperatures due to faster precipitation of ettringite. When using a calcium sulfate to calcium sulfoaluminate molar ratio of 1, higher d-values of ettringite peaks were observed at elevated temperatures, suggesting that more ions were released from the cement clinker at elevated temperatures, allowing a higher ion uptake in the ettringite structure. At a molar ratio of 2.5, less clinker is available in the cement, therefore these differences were not observed.
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Haselmann U, Haberfehlner G, Pei W, Popov MN, Romaner L, Knez D, Chen J, Ghasemi A, He Y, Kothleitner G, Zhang Z. Study on Ca Segregation toward an Epitaxial Interface between Bismuth Ferrite and Strontium Titanate. ACS APPLIED MATERIALS & INTERFACES 2020; 12:12264-12274. [PMID: 32058684 PMCID: PMC7068718 DOI: 10.1021/acsami.9b20505] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 02/14/2020] [Indexed: 06/10/2023]
Abstract
Segregation is a crucial phenomenon, which has to be considered in functional material design. Segregation processes in perovskite oxides have been the subject of ongoing scientific interest, since they can lead to a modification of properties and a loss of functionality. Many studies in oxide thin films have focused on segregation toward the surface using a variety of surface-sensitive analysis techniques. In contrast, here we report a Ca segregation toward an in-plane compressively strained heterostructure interface in a Ca- and Mn-codoped bismuth ferrite film. We are using advanced transmission electron microscopy techniques, X-ray photoelectron spectroscopy, and density functional theory (DFT) calculations. Ca segregation is found to trigger atomic and electronic structure changes at the interface. This includes the reduction of the interface strain according to the Ca concentration gradient, interplanar spacing variations, and oxygen vacancies at the interface. The experimental results are supported by DFT calculations, which explore two segregation scenarios, i.e., one without oxygen vacancies and Fe oxidation from 3+ to 4+ and one with vacancies for charge compensation. Comparison with electron energy loss spectroscopy (EELS) measurements confirms the second segregation scenario with vacancy formation. The findings contribute to the understanding of segregation and indicate promising effects of a Ca-rich buffer layer in this heterostructure system.
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Affiliation(s)
- Ulrich Haselmann
- Erich
Schmid Institute of Materials Science, Austrian
Academy of Sciences, Leoben 8700, Austria
| | - Georg Haberfehlner
- Institute
for Electron Microscopy and Nanoanalysis, Graz University of Technology, Graz 8010, Austria
| | - Weijie Pei
- School
of Materials Science & Engineering, Hubei University, Wuhan 430000, Hubei, China
| | - Maxim N. Popov
- Materials
Center Leoben Forschung GmbH, Leoben 8700, Austria
| | - Lorenz Romaner
- Materials
Center Leoben Forschung GmbH, Leoben 8700, Austria
| | - Daniel Knez
- Graz
Centre for Electron Microscopy, Graz 8010, Austria
| | - Jian Chen
- School
of Materials Science & Engineering, Hubei University, Wuhan 430000, Hubei, China
| | - Arsham Ghasemi
- Erich
Schmid Institute of Materials Science, Austrian
Academy of Sciences, Leoben 8700, Austria
| | - Yunbin He
- School
of Materials Science & Engineering, Hubei University, Wuhan 430000, Hubei, China
| | - Gerald Kothleitner
- Institute
for Electron Microscopy and Nanoanalysis, Graz University of Technology, Graz 8010, Austria
- Graz
Centre for Electron Microscopy, Graz 8010, Austria
| | - Zaoli Zhang
- Erich
Schmid Institute of Materials Science, Austrian
Academy of Sciences, Leoben 8700, Austria
- Institute
of Material Physics, Montanuniversität
Leoben, Leoben 8700, Austria
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4
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Choi EM, Zhu B, Lu P, Feighan J, Sun X, Wang H, MacManus-Driscoll JL. Magnetic signatures of 120 K superconductivity at interfaces in La 2CuO 4+δ. NANOSCALE 2020; 12:3157-3165. [PMID: 31967155 DOI: 10.1039/c9nr04996g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
In self-assembled vertically aligned nanocomposite (VAN) thin films of La2CuO4+δ + LaCuO3, we find from DC magnetic susceptibility measurements, weak signatures of superconductivity at ∼120 K. This compares to a maximum TC of 40 K in bulk La2CuO4+δ. The 120 K signature occurs only when both c-axis and a-axis oriented La2CuO4+δ grains are present in the films. The superconductivity was lost after 3 months of storage but was recovered by annealing in oxygen. From lattice parameter analyses undertaken close to the c/a grain boundaries, it was determined that expansion of the La perovskite block in c-La2CuO4+δ enables the differently oriented grains to join at the interface. This expansion is consistent with the higher TC interfacial region. The work shows a new direction for increasing TC in cuprates - namely careful strain engineering of the crystal structure independently in-plane and out-of-plane.
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Affiliation(s)
- Eun-Mi Choi
- Department of Materials Science & Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, CB3 0FS, UK.
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5
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Choi EM, Di Bernardo A, Zhu B, Lu P, Alpern H, Zhang KHL, Shapira T, Feighan J, Sun X, Robinson J, Paltiel Y, Millo O, Wang H, Jia Q, MacManus-Driscoll JL. 3D strain-induced superconductivity in La 2CuO 4+δ using a simple vertically aligned nanocomposite approach. SCIENCE ADVANCES 2019; 5:eaav5532. [PMID: 31032414 PMCID: PMC6486216 DOI: 10.1126/sciadv.aav5532] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 03/07/2019] [Indexed: 05/28/2023]
Abstract
A long-term goal for superconductors is to increase the superconducting transition temperature, T C. In cuprates, T C depends strongly on the out-of-plane Cu-apical oxygen distance and the in-plane Cu-O distance, but there has been little attention paid to tuning them independently. Here, in simply grown, self-assembled, vertically aligned nanocomposite thin films of La2CuO4+δ + LaCuO3, by strongly increasing out-of-plane distances without reducing in-plane distances (three-dimensional strain engineering), we achieve superconductivity up to 50 K in the vertical interface regions, spaced ~50 nm apart. No additional process to supply excess oxygen, e.g., by ozone or high-pressure oxygen annealing, was required, as is normally the case for plain La2CuO4+δ films. Our proof-of-concept work represents an entirely new approach to increasing T C in cuprates or other superconductors.
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Affiliation(s)
- Eun-Mi Choi
- Department of Materials Science & Metallurgy, University of Cambridge, Cambridge, UK
| | - Angelo Di Bernardo
- Department of Materials Science & Metallurgy, University of Cambridge, Cambridge, UK
| | - Bonan Zhu
- Department of Materials Science & Metallurgy, University of Cambridge, Cambridge, UK
| | - Ping Lu
- Sandia National Laboratories, Albuquerque, NM 87185, USA
| | - Hen Alpern
- Racah Institute of Physics and Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Kelvin H. L. Zhang
- Department of Materials Science & Metallurgy, University of Cambridge, Cambridge, UK
| | - Tamar Shapira
- Racah Institute of Physics and Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - John Feighan
- Department of Materials Science & Metallurgy, University of Cambridge, Cambridge, UK
| | - Xing Sun
- Department of Materials Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Jason Robinson
- Department of Materials Science & Metallurgy, University of Cambridge, Cambridge, UK
| | - Yossi Paltiel
- Department of Applied Physics and Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Oded Millo
- Racah Institute of Physics and Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Haiyan Wang
- Department of Materials Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Quanxi Jia
- Department of Materials Design and Innovation, University at Buffalo—The State University of New York, Buffalo, NY, USA
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6
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Dholabhai PP, Martinez E, Uberuaga BP. Influence of Chemistry and Misfit Dislocation Structure on Dopant Segregation at Complex Oxide Heterointerfaces. ADVANCED THEORY AND SIMULATIONS 2018. [DOI: 10.1002/adts.201800095] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Pratik P. Dholabhai
- School of Physics and Astronomy Rochester Institute of Technology Rochester NY 14623 USA
| | - Enrique Martinez
- Materials Science and Technology Division Los Alamos National Laboratory Los Alamos NM 87545 USA
| | - Blas P. Uberuaga
- Materials Science and Technology Division Los Alamos National Laboratory Los Alamos NM 87545 USA
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7
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Kaya P, Gregori G, Baiutti F, Yordanov P, Suyolcu YE, Cristiani G, Wrobel F, Benckiser E, Keimer B, van Aken PA, Habermeier HU, Logvenov G, Maier J. High-Temperature Thermoelectricity in LaNiO 3-La 2CuO 4 Heterostructures. ACS APPLIED MATERIALS & INTERFACES 2018; 10:22786-22792. [PMID: 29927575 DOI: 10.1021/acsami.8b02153] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Transition metal oxides exhibit a high potential for application in the field of electronic devices, energy storage, and energy conversion. The ability of building these types of materials by atomic layer-by-layer techniques provides a possibility to design novel systems with favored functionalities. In this study, by means of the atomic layer-by-layer oxide molecular beam epitaxy technique, we designed oxide heterostructures consisting of tetragonal K2NiF4-type insulating La2CuO4 (LCO) and perovskite-type conductive metallic LaNiO3 (LNO) layers with different thicknesses to assess the heterostructure-thermoelectric property-relationship at high temperatures. We observed that the transport properties depend on the constituent layer thickness, interface intermixing, and oxygen-exchange dynamics in the LCO layers, which occurs at high temperatures. As the thickness of the individual layers was reduced, the electrical conductivity decreased and the sign of the Seebeck coefficient changed, revealing the contribution of the individual layers where possible interfacial contributions cannot be ruled out. High-resolution scanning transmission electron microscopy investigations showed that a substitutional solid solution of La2(CuNi)O4 was formed when the thickness of the constituent layers was decreased.
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Affiliation(s)
- Pinar Kaya
- Max Planck Institute for Solid State Research , Heisenbergstr. 1 , D-70569 Stuttgart , Germany
| | - Giuliano Gregori
- Max Planck Institute for Solid State Research , Heisenbergstr. 1 , D-70569 Stuttgart , Germany
| | - Federico Baiutti
- Max Planck Institute for Solid State Research , Heisenbergstr. 1 , D-70569 Stuttgart , Germany
| | - Petar Yordanov
- Max Planck Institute for Solid State Research , Heisenbergstr. 1 , D-70569 Stuttgart , Germany
| | - Y Eren Suyolcu
- Max Planck Institute for Solid State Research , Heisenbergstr. 1 , D-70569 Stuttgart , Germany
| | - Georg Cristiani
- Max Planck Institute for Solid State Research , Heisenbergstr. 1 , D-70569 Stuttgart , Germany
| | - Friederike Wrobel
- Max Planck Institute for Solid State Research , Heisenbergstr. 1 , D-70569 Stuttgart , Germany
| | - Eva Benckiser
- Max Planck Institute for Solid State Research , Heisenbergstr. 1 , D-70569 Stuttgart , Germany
| | - Bernhard Keimer
- Max Planck Institute for Solid State Research , Heisenbergstr. 1 , D-70569 Stuttgart , Germany
| | - Peter A van Aken
- Max Planck Institute for Solid State Research , Heisenbergstr. 1 , D-70569 Stuttgart , Germany
| | - Hanns-Ulrich Habermeier
- Max Planck Institute for Solid State Research , Heisenbergstr. 1 , D-70569 Stuttgart , Germany
| | - Gennady Logvenov
- Max Planck Institute for Solid State Research , Heisenbergstr. 1 , D-70569 Stuttgart , Germany
| | - Joachim Maier
- Max Planck Institute for Solid State Research , Heisenbergstr. 1 , D-70569 Stuttgart , Germany
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8
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Baiutti F, Gregori G, Suyolcu YE, Wang Y, Cristiani G, Sigle W, van Aken PA, Logvenov G, Maier J. High-temperature superconductivity at the lanthanum cuprate/lanthanum-strontium nickelate interface. NANOSCALE 2018; 10:8712-8720. [PMID: 29701210 DOI: 10.1039/c8nr00885j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The utilization of interface effects in epitaxial systems at the nanoscale has emerged as a very powerful approach for engineering functional properties of oxides. Here we present a novel structure fabricated by a state-of-the-art oxide molecular beam epitaxy method and consisting of lanthanum cuprate and strontium (Sr)-doped lanthanum nickelate, in which interfacial high-temperature superconductivity (Tc up to 40 K) occurs at the contact between the two phases. In such a system, we are able to tune the superconducting properties simply by changing the structural parameters. By employing electron spectroscopy and microscopy combined with dedicated conductivity measurements, we show that decoupling occurs between the electronic charge carrier and the cation (Sr) concentration profiles at the interface and that a hole accumulation layer forms, which dictates the resulting superconducting properties. Such effects are rationalized in the light of a generalized space-charge theory for oxide systems that takes account of both ionic and electronic redistribution effects.
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Affiliation(s)
- F Baiutti
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart, Germany.
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