Structural and electrical characterisation of some ABO₃ perovskites
type: CreativeWork
description: Powder X-ray diffraction and Raman spectroscopy have been used to characterise the electrolyte materials La₁₋ₓSrₓGaO₃₋δ (x = 0-0.2) and LaGa₁₋yMyO₃₋δ (y = 0-0.2, M = Cr, Mg). XRD of La₁₋ₓSrₓGaO₃₋δ (x = 0-0.2) showed the secondary phase of SrGa₃O₇ at >5 mol% Sr. The cell deformed with increasing Sr dopant concentration. In the XRD patterns of LaGa₁₋yCryO₃₋δ (y = 0-0.2) the cell also deformed with increasing Cr dopant concentration. The peak at ca. 32° showed a second peak at 32.37°, likely to be due to a phase change, since the peaks did not alter in relative intensity with increase in dopant concentration (above x = 0). LaGa₁₋yMgyO₃₋δ (y = 0-0.2) showed, from the powder X-ray diffraction pattern, the formation of the secondary phase of La₄Ga₂O₉ at >5 mol% Mg. Raman spectra of LaGaO₃ showed 18 features at room temperature, and 14 at -196 °C with the disappearance of the band at 92 cm⁻¹. Raman spectra of the doped material, LaGa₁₋yMgyO₃₋δ at y = 0-0.2 showed the formation of a secondary phase of La₄Ga₂O₉ with bands at 243, 295 and 356 cm⁻¹ which become more predominant at 20 mol % Mg. LaFeO₃ was prepared using a reverse-strike coprecipitation method. The Raman spectrum of LaFeO₃ were obtained at both low-temperature and room temperature, with 9 bands observed of a predicted 24 Raman active modes. Mode assignment was determined from comparison of the Raman profile and band position with perovskites with the same structure, namely, SmAlO₃ and LaGaO₃ and are as follows: 102 (B₁g ), ca.140 (B₂g), 150 (B₁g), 176 (Ag), 227 (B₃g), 261 (Ag), 289 (Ag), 413 (Ag), 429 (B₃g). LaFe₁₋ₓMgₓO₃ was prepared using a reverse-strike coprecipitation method. The XRD patterns obtained at room temperature showed single phase, but also included small amounts of impurity of La₂O₃ and La₂MgOₓ. Lattice calculations based on FeLaO₃ showed that Mg dopant concentration had a minor effect on the overall unit cell volume, with the minimum volume achieved being 241.68Å³ at 1450 °C, 15%Mg concentration.…
abstract: Powder X-ray diffraction and Raman spectroscopy have been used to characterise the electrolyte materials La₁₋ₓSrₓGaO₃₋δ (x = 0-0.2) and LaGa₁₋yMyO₃₋δ (y = 0-0.2, M = Cr, Mg). XRD of La₁₋ₓSrₓGaO₃₋δ (x = 0-0.2) showed the secondary phase of SrGa₃O₇ at >5 mol% Sr. The cell deformed with increasing Sr dopant concentration. In the XRD patterns of LaGa₁₋yCryO₃₋δ (y = 0-0.2) the cell also deformed with increasing Cr dopant concentration. The peak at ca. 32° showed a second peak at 32.37°, likely to be due to a phase change, since the peaks did not alter in relative intensity with increase in dopant concentration (above x = 0). LaGa₁₋yMgyO₃₋δ (y = 0-0.2) showed, from the powder X-ray diffraction pattern, the formation of the secondary phase of La₄Ga₂O₉ at >5 mol% Mg. Raman spectra of LaGaO₃ showed 18 features at room temperature, and 14 at -196 °C with the disappearance of the band at 92 cm⁻¹. Raman spectra of the doped material, LaGa₁₋yMgyO₃₋δ at y = 0-0.2 showed the formation of a secondary phase of La₄Ga₂O₉ with bands at 243, 295 and 356 cm⁻¹ which become more predominant at 20 mol % Mg. LaFeO₃ was prepared using a reverse-strike coprecipitation method. The Raman spectrum of LaFeO₃ were obtained at both low-temperature and room temperature, with 9 bands observed of a predicted 24 Raman active modes. Mode assignment was determined from comparison of the Raman profile and band position with perovskites with the same structure, namely, SmAlO₃ and LaGaO₃ and are as follows: 102 (B₁g ), ca.140 (B₂g), 150 (B₁g), 176 (Ag), 227 (B₃g), 261 (Ag), 289 (Ag), 413 (Ag), 429 (B₃g). LaFe₁₋ₓMgₓO₃ was prepared using a reverse-strike coprecipitation method. The XRD patterns obtained at room temperature showed single phase, but also included small amounts of impurity of La₂O₃ and La₂MgOₓ. Lattice calculations based on FeLaO₃ showed that Mg dopant concentration had a minor effect on the overall unit cell volume, with the minimum volume achieved being 241.68Å³ at 1450 °C, 15%Mg concentration.…
author: Phillips, Roslyn June
license: https://researchcommons.waikato.ac.nz/bitstreams/45b20647-d12b-4950-9cb0-c1d24bd1c01b/download
date published: 1999
date modified: 2026-07-24T05:57:52Z
provider: University Waikato
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: The University of Waikato