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Grendal OG, Fitch AN, Aamlid SS. A-Site Cation Disorder in Sr xBa 1-xNb 2O 6 ( x = 0.25, 0.33, 0.50, 0.61) Studied by High-Resolution Resonant X-ray Powder Diffraction. ACS OMEGA 2023; 8:37592-37599. [PMID: 37841140 PMCID: PMC10568720 DOI: 10.1021/acsomega.3c06500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 09/14/2023] [Indexed: 10/17/2023]
Abstract
The dielectric and ferroelectric properties of SrxBa1-xNb2O6 (SBN, 0.2 < x < 0.8) are known to be affected by the Sr fraction and can be further controlled by various quenching schemes. Changes in A-site cation configuration are believed to be linked to these changes in properties. In this work, we study the A-site cation disorder in SBN by the use of high-resolution resonant X-ray powder diffraction. The experimental results show that the larger Ba2+ is found exclusively on the larger A2 site, while Sr2+ is found on both the A1 and A2 sites, with an increasing amount on A2 with an increasing Sr fraction. At elevated temperatures, a small migration of Sr2+ from A1 to A2 is observed for SBN50 and SBN61. Linking this change in occupancies to changes in the average cation size on the A1 and A2 sites allows for rationalization of the property changes observed for quenched samples. Furthermore, SBN25 is shown to deviate from the tetragonal P4bm structure and is found to be orthorhombic with a Cmm2 structure.
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Affiliation(s)
- Ola G. Grendal
- European
Synchrotron Radiation Facility (ESRF), 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Andrew N. Fitch
- European
Synchrotron Radiation Facility (ESRF), 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Solveig S. Aamlid
- Stewart
Blusson Quantum Matter Institute, The University
of British Columbia, 2355 East Mall, V6T 1Z4 Vancouver, British Columbia, Canada
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2
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Wang BX, Krogstad MJ, Zheng H, Osborn R, Rosenkranz S, Phelan D. Active and passive defects in tetragonal tungsten bronze relaxor ferroelectrics. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:405401. [PMID: 35853443 DOI: 10.1088/1361-648x/ac8261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 07/19/2022] [Indexed: 06/15/2023]
Abstract
Tetragonal tungsten bronze (TTB) based oxides constitute a large family of dielectric materials which are known to exhibit complex distortions producing incommensurately modulated superstructures as well as significant local deviations from their average symmetry. The local deviations produce diffuse scattering in diffraction experiments. The structure as well as the charge dynamics of these materials are anticipated to be sensitive to defects, such as cation or oxygen vacancies. In this work, in an effort to understand how the structural and charge dynamical properties respond to these two types of vacancy defects, we have performed measurements of dielectric susceptibilities and single crystal diffraction experiments of two types of TTB materials with both 'filled' (Ba2NdFeNb4O15and Ba2PrFeNb4O15) and 'unfilled' (Sr0.5Ba0.5Nb2O6) cation sublattices. We also perform these measurements before and after oxygen annealing, which alters the oxygen vacancy concentrations. Surprisingly, we find that many of the diffuse scattering features that are present in the unfilled structure are also present in the filled structure, suggesting that the random fields and disorder that are characteristic of the unfilled structure are not responsible for many of the local structural features that are reflected in the diffuse scattering. Oxygen annealing clearly affected both color and dielectric properties, consistent with a diminishment of the oxygen vacancy concentration, but had little effect on observed diffuse patterns.
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Affiliation(s)
- Bi-Xia Wang
- Materials Science Division, Argonne National Laboratory, Lemont, IL 60439, United States of America
| | - M J Krogstad
- Materials Science Division, Argonne National Laboratory, Lemont, IL 60439, United States of America
- Advanced Photon Source, Argonne National Laboratory, Lemont, IL 60439, United States of America
| | - H Zheng
- Materials Science Division, Argonne National Laboratory, Lemont, IL 60439, United States of America
| | - R Osborn
- Materials Science Division, Argonne National Laboratory, Lemont, IL 60439, United States of America
| | - S Rosenkranz
- Materials Science Division, Argonne National Laboratory, Lemont, IL 60439, United States of America
| | - D Phelan
- Materials Science Division, Argonne National Laboratory, Lemont, IL 60439, United States of America
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3
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Grendal OG, Blichfeld AB, Vu TD, van Beek W, Selbach SM, Grande T, Einarsrud MA. Composition and morphology tuning during hydrothermal synthesis of SrxBa1−xNb2O6 tetragonal tungsten bronzes studied by in situ X-ray diffraction. CrystEngComm 2019. [DOI: 10.1039/c9ce01049a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Advanced in situ techniques provide knowledge about crystal growth mechanisms of SrxBa1−xNb2O6 facilitating the design of the microstructure and the determination of stoichiometry.
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Affiliation(s)
- Ola G. Grendal
- Department of Materials Science and Engineering
- NTNU Norwegian University of Science and Technology
- 7491 Trondheim
- Norway
| | - Anders B. Blichfeld
- Department of Materials Science and Engineering
- NTNU Norwegian University of Science and Technology
- 7491 Trondheim
- Norway
| | - Tuong D. Vu
- Department of Materials Science and Engineering
- NTNU Norwegian University of Science and Technology
- 7491 Trondheim
- Norway
| | - Wouter van Beek
- Swiss-Norwegian Beamlines at European Synchrotron Research Facility
- 38043 Grenoble
- France
| | - Sverre M. Selbach
- Department of Materials Science and Engineering
- NTNU Norwegian University of Science and Technology
- 7491 Trondheim
- Norway
| | - Tor Grande
- Department of Materials Science and Engineering
- NTNU Norwegian University of Science and Technology
- 7491 Trondheim
- Norway
| | - Mari-Ann Einarsrud
- Department of Materials Science and Engineering
- NTNU Norwegian University of Science and Technology
- 7491 Trondheim
- Norway
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4
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Ottini R, Tealdi C, Tomasi C, Tredici IG, Soffientini A, Burriel R, Palacios E, Castro M, Anselmi-Tamburini U, Ghigna P, Spinolo G. Local environments and transport properties of heavily doped strontium barium niobates Sr0.5Ba0.5Nb2O6. J SOLID STATE CHEM 2018. [DOI: 10.1016/j.jssc.2017.09.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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5
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Graetsch HA. Structural changes of relaxor ferroelectric Sr 0.52Ba 0.48Nb 2O 6 (SBN52) on quenching and reheating. ACTA CRYSTALLOGRAPHICA SECTION B, STRUCTURAL SCIENCE, CRYSTAL ENGINEERING AND MATERIALS 2017; 73:820-826. [PMID: 28980985 DOI: 10.1107/s2052520617007880] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 05/26/2017] [Indexed: 06/07/2023]
Abstract
Quenching of Sr0.52Ba0.48Nb2O6 (SBN52) from temperatures above 700°C causes small modifications in the strontium distribution over the large cation sites (Me1 and Me2), changed off-centre shifts of the Nb atoms and slightly increased modulation amplitudes. The higher disorder of cation incorporation can explain the enhanced ferroelectric properties. The quenched structural disorder can be healed by reheating followed by slow cooling. A change of the modulation dimension on quenching such as for CaxBa1-xNb2O6 (CBN) mixed crystals was not observed.
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Affiliation(s)
- Heribert A Graetsch
- Institut für Geologie, Mineralogie und Geophysik, Ruhr-Universität Bochum, Universitätsstrasse 150, Bochum, D-44801, Germany
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6
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Graetsch H. Large structural modulations in the relaxor ferroelectric and intermediate state of strontium rich members (x>0.6) of the SrxBa1−xNb2O6 (sbn) solid solution series. J SOLID STATE CHEM 2017. [DOI: 10.1016/j.jssc.2016.11.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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7
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Paria Sena R, Babaryk AA, Khainakov S, Garcia-Granda S, Slobodyanik NS, Van Tendeloo G, Abakumov AM, Hadermann J. A pseudo-tetragonal tungsten bronze superstructure: a combined solution of the crystal structure of K6.4(Nb,Ta)36.3O94 with advanced transmission electron microscopy and neutron diffraction. Dalton Trans 2016; 45:973-9. [DOI: 10.1039/c5dt03479e] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
K6.4Nb28.2Ta8.1O94 has the same framework as literature's K2Nb8O21 but a different distribution of cations over different channels.
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Affiliation(s)
- Robert Paria Sena
- Electron Microscopy for Materials Research (EMAT)
- University of Antwerp
- Antwerp
- Belgium
| | - Artem A. Babaryk
- Faculty of Chemistry
- Taras Shevchenko National University of Kyiv
- 01601 Kyiv
- Ukraine
- Department of Physical and Inorganic Chemistry
| | - Sergiy Khainakov
- Department of Physical and Inorganic Chemistry
- Faculty of Chemistry
- University of Oviedo
- 33006 Oviedo
- Spain
| | - Santiago Garcia-Granda
- Department of Physical and Inorganic Chemistry
- Faculty of Chemistry
- University of Oviedo
- 33006 Oviedo
- Spain
| | | | - Gustaaf Van Tendeloo
- Electron Microscopy for Materials Research (EMAT)
- University of Antwerp
- Antwerp
- Belgium
| | - Artem M. Abakumov
- Electron Microscopy for Materials Research (EMAT)
- University of Antwerp
- Antwerp
- Belgium
| | - Joke Hadermann
- Electron Microscopy for Materials Research (EMAT)
- University of Antwerp
- Antwerp
- Belgium
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Graetsch HA, Pandey CS, Schreuer J, Burianek M, Mühlberg M. Incommensurate modulations of relaxor ferroelectric Ca0.24Ba0.76Nb2O6 (CBN24) and Ca0.31Ba0.69Nb2O6 (CBN31). ACTA CRYSTALLOGRAPHICA SECTION B, STRUCTURAL SCIENCE, CRYSTAL ENGINEERING AND MATERIALS 2014; 70:743-749. [PMID: 25080253 DOI: 10.1107/s2052520614011676] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 05/20/2014] [Indexed: 06/03/2023]
Abstract
CBN crystals show a one- and a two-dimensionally modulated modification. The former is isotypic with orthorhombic Ba4Na2Nb10O30 and the latter with the tetragonal tungsten bronze type of crystal structure. The orthorhombic form irreversibly transforms to the tetragonal polymorph at the ferroelectric phase transition near 603 K. Orthorhombic and tetragonal CBN24 slightly differ in the distribution of the Ba and Ca atoms over the incompletely filled Me1 and Me2 sites. The tetragonal symmetry is further broken in orthorhombic CBN24 by different amplitudes of the positional modulations of O atoms which are symmetrically equivalent in the TTB structure. A similar orthorhombic phase of CBN31 could be obtained by quenching from 1473 K.
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Affiliation(s)
- Heribert A Graetsch
- Institut für Geologie, Mineralogie und Geophysik, Ruhr-Universität Bochum, Universitätsstraße 150, Bochum D-44801, Germany
| | - Chandra Shehkar Pandey
- Institut für Geologie, Mineralogie und Geophysik, Ruhr-Universität Bochum, Universitätsstraße 150, Bochum D-44801, Germany
| | - Jürgen Schreuer
- Institut für Geologie, Mineralogie und Geophysik, Ruhr-Universität Bochum, Universitätsstraße 150, Bochum D-44801, Germany
| | - Manfred Burianek
- Institut für Kristallographie, Universität zu Köln, Zülpicher Straße 49b, Köln D-50674, Germany
| | - Manfred Mühlberg
- Institut für Kristallographie, Universität zu Köln, Zülpicher Straße 49b, Köln D-50674, Germany
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Smirnov M, Saint-Grégoire P. Unified approach for determining tetragonal tungsten bronze crystal structures. ACTA CRYSTALLOGRAPHICA A-FOUNDATION AND ADVANCES 2014; 70:283-90. [PMID: 24815976 DOI: 10.1107/s2053273314003994] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 02/20/2014] [Indexed: 11/10/2022]
Abstract
Tetragonal tungsten bronze (TTB) oxides are one of the most important classes of ferroelectrics. Many of these framework structures undergo ferroelastic transformations related to octahedron tilting deformations. Such tilting deformations are closely related to the rigid unit modes (RUMs). This paper discusses the whole set of RUMs in an ideal TTB lattice and possible crystal structures which can emerge owing to the condensation of some of them. Analysis of available experimental data for the TTB-like niobates lends credence to the obtained theoretical predictions.
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Affiliation(s)
- M Smirnov
- Faculty of Physics, St Petersburg State University, Petrodvoretz, 194508 St Petersburg, Russia
| | - P Saint-Grégoire
- Laboratoire MIPA, University of Nîmes, 30021 Nîmes cedex, France
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10
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Graetsch HA. Changes of the crystal structure at the relaxor ferroelectric phase transition of strontium barium niobate (SBN53). CRYSTAL RESEARCH AND TECHNOLOGY 2014. [DOI: 10.1002/crat.201300281] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- H. A. Graetsch
- Institut für Geologie, Mineralogie und Geophysik; Ruhr-Universität Bochum; D-44780 Bochum Germany
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11
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Stachowicz M, Gawryszewska O, Swirkowicz MA, Lukasiewicz T. SBN60, strontium-barium niobate at 100 K. Acta Crystallogr Sect E Struct Rep Online 2013; 69:i69-i70. [PMID: 24098159 PMCID: PMC3790337 DOI: 10.1107/s1600536813025142] [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: 06/05/2013] [Accepted: 09/10/2013] [Indexed: 11/10/2022]
Abstract
The title compound, Sr0.6Ba0.4Nb2O6 (strontium barium niobium oxide), belongs to the group of strontium-barium niobates with varying composition of Sr and Ba. Their general formula can be written as Sr x Ba1 - x Nb2O6. Below the Curie temperature, T c , these materials indicate ferroelectric properties. The Curie temperature for SBN60 is equal to 346±0.5 K so the structure is in the ferroelectric phase at the measurement temperature of 100 K. Characteristic for this family of compounds is the packing along the z-axis. The NbO6 corner-sharing octa-hedra surround three types of vacancy tunnels with penta-gonal, square and triangular shapes. The Sr(2+) ions partially occupy two unique sites, the first one located inside the penta-gon and the second one in the square tunnels. Consequently, they are situated on the mirror plane and the inter-section of two glide planes, respectively. The site inside the penta-gonal tunnel is additionally disordered so that the same position is shared by Ba(2+) and Sr(2+) ions whereas another part of the Ba(2+) ion occupies a different position (relative occupancies 0.43:0.41:0.16). One of the Nb(V) atoms and three of the O(2-) ions occupy general positions. The second Nb(V) atom is located on the inter-section of the mirror planes. Two remaining O(2-) ions are located on the same mirror plane. Only the Nb(V) atom and one of the O(2-) ions which is located on the mirror plane are not disordered. Each of the remaining O(2-) ions is split between two sites, with relative occupancies of 0.52:0.48 (O(2-) ions in general positions) and 0.64:0.36 (O(2-) ion on the mirror plane).
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Affiliation(s)
- Marcin Stachowicz
- Chemistry Department, Uniwersity of Warsaw, 1 Pasteura Str., 02-093, Warsaw, Poland
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