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Title: Characterization of ordering in A-site deficient perovskite Ca 1–xLa 2x/3TiO 3 using STEM/EELS

Abstract

The vacancy ordering behavior of an A-site deficient perovskite system, Ca 1–xLa 2x/3TiO 3, was studied using atomic resolution scanning transmission electron microscopy (STEM) in conjunction with electron energy-loss spectroscopy (EELS), with the aim of determining the role of A-site composition changes. At low La content (x = 0.2), adopting Pbnm symmetry, there was no indication of long-range ordering. Domains, with clear boundaries, were observed in bright-field (BF) imaging, but were not immediately visible in the corresponding high-angle annular dark-field (HAADF) image. These boundaries, with the aid of displacement maps from A-site cations in the HAADF signal, are shown to be tilt boundaries. At the La-rich end of the composition (x = 0.9), adopting Cmmm symmetry, long-range ordering of vacancies and La 3+ ions was observed, with alternating La-rich and La-poor layers on (001)p planes, creating a double perovskite lattice along the c axis. These highly ordered domains can be found isolated within a random distribution of vacancies/La 3+, or within a large population, encompassing a large volume. In regions with a high number density of double perovskite domains, these highly ordered domains were separated by twin boundaries, with 90° or 180° lattice rotations across boundaries. In conclusion, the occurrencemore » and characteristics of these ordered structures are discussed and compared with similar perovskite systems.« less

Authors:
 [1];  [2];  [2];  [3];  [4];  [5];  [1];  [1];  [1];  [6]
  1. Univ. of Oxford, Oxford (United Kingdom)
  2. SuperSTEM Lab., Warrington (United Kingdom)
  3. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  4. Univ. of Sheffield, Sheffield (United Kingdom); Univ. of Liverpool, Liverpool (United Kingdom)
  5. Univ. of Sheffield, Sheffield (United Kingdom)
  6. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)
OSTI Identifier:
1328524
Alternate Identifier(s):
OSTI ID: 1329131; OSTI ID: 1440000
Grant/Contract Number:
AC05-00OR22725; AC02-05CH11231
Resource Type:
Journal Article: Published Article
Journal Name:
Inorganic Chemistry
Additional Journal Information:
Journal Volume: 55; Journal Issue: 19; Journal ID: ISSN 0020-1669
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Danaie, Mohsen, Kepaptsoglou, Demie, Ramasse, Quentin M., Ophus, Colin, Whittle, Karl R., Lawson, Sebastian M., Pedrazzini, Stella, Young, Neil P., Bagot, Paul A. J., and Edmondson, Philip D.. Characterization of ordering in A-site deficient perovskite Ca1–xLa 2x/3TiO3 using STEM/EELS. United States: N. p., 2016. Web. doi:10.1021/acs.inorgchem.6b02087.
Danaie, Mohsen, Kepaptsoglou, Demie, Ramasse, Quentin M., Ophus, Colin, Whittle, Karl R., Lawson, Sebastian M., Pedrazzini, Stella, Young, Neil P., Bagot, Paul A. J., & Edmondson, Philip D.. Characterization of ordering in A-site deficient perovskite Ca1–xLa 2x/3TiO3 using STEM/EELS. United States. doi:10.1021/acs.inorgchem.6b02087.
Danaie, Mohsen, Kepaptsoglou, Demie, Ramasse, Quentin M., Ophus, Colin, Whittle, Karl R., Lawson, Sebastian M., Pedrazzini, Stella, Young, Neil P., Bagot, Paul A. J., and Edmondson, Philip D.. Thu . "Characterization of ordering in A-site deficient perovskite Ca1–xLa 2x/3TiO3 using STEM/EELS". United States. doi:10.1021/acs.inorgchem.6b02087.
@article{osti_1328524,
title = {Characterization of ordering in A-site deficient perovskite Ca1–xLa 2x/3TiO3 using STEM/EELS},
author = {Danaie, Mohsen and Kepaptsoglou, Demie and Ramasse, Quentin M. and Ophus, Colin and Whittle, Karl R. and Lawson, Sebastian M. and Pedrazzini, Stella and Young, Neil P. and Bagot, Paul A. J. and Edmondson, Philip D.},
abstractNote = {The vacancy ordering behavior of an A-site deficient perovskite system, Ca1–xLa2x/3TiO3, was studied using atomic resolution scanning transmission electron microscopy (STEM) in conjunction with electron energy-loss spectroscopy (EELS), with the aim of determining the role of A-site composition changes. At low La content (x = 0.2), adopting Pbnm symmetry, there was no indication of long-range ordering. Domains, with clear boundaries, were observed in bright-field (BF) imaging, but were not immediately visible in the corresponding high-angle annular dark-field (HAADF) image. These boundaries, with the aid of displacement maps from A-site cations in the HAADF signal, are shown to be tilt boundaries. At the La-rich end of the composition (x = 0.9), adopting Cmmm symmetry, long-range ordering of vacancies and La3+ ions was observed, with alternating La-rich and La-poor layers on (001)p planes, creating a double perovskite lattice along the c axis. These highly ordered domains can be found isolated within a random distribution of vacancies/La3+, or within a large population, encompassing a large volume. In regions with a high number density of double perovskite domains, these highly ordered domains were separated by twin boundaries, with 90° or 180° lattice rotations across boundaries. In conclusion, the occurrence and characteristics of these ordered structures are discussed and compared with similar perovskite systems.},
doi = {10.1021/acs.inorgchem.6b02087},
journal = {Inorganic Chemistry},
number = 19,
volume = 55,
place = {United States},
year = {Thu Sep 15 00:00:00 EDT 2016},
month = {Thu Sep 15 00:00:00 EDT 2016}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1021/acs.inorgchem.6b02087

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Cited by: 3works
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  • The vacancy ordering behavior of an A-site deficient perovskite system, Ca 1–xLa 2x/3TiO 3, was studied using atomic resolution scanning transmission electron microscopy (STEM) in conjunction with electron energy-loss spectroscopy (EELS), with the aim of determining the role of A-site composition changes. At low La content (x = 0.2), adopting Pbnm symmetry, there was no indication of long-range ordering. Domains, with clear boundaries, were observed in bright-field (BF) imaging, but were not immediately visible in the corresponding high-angle annular dark-field (HAADF) image. These boundaries, with the aid of displacement maps from A-site cations in the HAADF signal, are shown tomore » be tilt boundaries. At the La-rich end of the composition (x = 0.9), adopting Cmmm symmetry, long-range ordering of vacancies and La 3+ ions was observed, with alternating La-rich and La-poor layers on (001)p planes, creating a double perovskite lattice along the c axis. These highly ordered domains can be found isolated within a random distribution of vacancies/La 3+, or within a large population, encompassing a large volume. In regions with a high number density of double perovskite domains, these highly ordered domains were separated by twin boundaries, with 90° or 180° lattice rotations across boundaries. In conclusion, the occurrence and characteristics of these ordered structures are discussed and compared with similar perovskite systems.« less
  • A solid solution system of the double perovskite La{sub 2/3}TiO{sub 3} and the GdFeO{sub 3}-type perovskite CaTiO{sub 3}, (1{minus})xCaTiO{sub 3}-xLa{sub 2/3}TiO{sub 3} has been prepared to investigate the crystal structure and the dielectric properties. In this system, the structure changed from pseudo-cubic perovskite to tetragonal double perovskite at x{approx}0.7, and to orthorhombic double perovskite at x{approx}0.9. Microwave dielectric measurement showed a decrease in dielectric constant and temperature coefficient of the resonant frequency and an increase in Q value with increasing x. The sample with x{approx}0.96 showed excellent microwave characteristics, especially high Q(2700) along with high {var_epsilon}{sub r} at 10 GHz.more » In the low frequency dielectric measurement, dielectric relaxation could be observed in the composition range x{le}0.3. The dielectric relaxation showed strikingly different behaviors depending on the annealing process in oxygen after sintering.« less
  • The (Ca{sub 1-2x}Na{sub x}La{sub x})TiO{sub 3} (0=<x=<0.5) A-site substituted perovskite compounds have been synthesized and characterized by XRD and Raman spectroscopy at room temperature. The XRD powder diffraction study suggests that the end-member Na{sub 1/2}La{sub 1/2}TiO{sub 3} crystallizes in the tetragonal space group I4/mcm. The phase transition from Pbnm to I4/mcm is located between x=0.34 and 0.39 and is driven by the variation of ionic radii at the A-site. The observed Raman modes are in agreement with group theory analysis, and the relationships between the behavior of structural parameters (e.g. Ti-O-Ti bond angle), indicated by long-range order, and the correspondingmore » Raman frequency shifts and intensity evolution, indicated by short-range order, are established and discussed in terms of the radius effect and the mass effect.« less
  • La[sub 0.67[minus]x]Li[sub 3x]TiO[sub 3] solid solution forms in the range [approximately]0.15 > x > [approximately]0.04 by the substitution mechanism La[r equilibrium]3Li. Superstructure reflections observed in this range are consistent with a superlattice consisting of the stacking of two perovskite subcells. A line-splitting phenomenon observed for x < [approximately]0.1 indicates that the tetragonal distortion of the cubic perovskite subcell occurs. The solid solutions exhibit high lithium ion conductivities greater than 10[sup [minus]4] S cm [sup [minus]1] at room temperature in a wide range, x > [approximately]0.04. A maximum conductivity of 1.1 [times] 10[sup [minus]3] S cm[sup [minus]1] is found at xmore » [approx] 0.1. The dome-shaped composition dependence of conductivity indicates that the conduction mechanism involves the movement of lithium ions through the A-site vacancies.« less