{"id":{"repo_id":"waikato-masters","oai_identifier":"oai:researchcommons.waikato.ac.nz:10289/15454"},"canonical_url":"https://search.dev.ndltd.org/etd/waikato-masters/oai:researchcommons.waikato.ac.nz:10289/15454","repository":{"repo_id":"waikato-masters","name":"University Waikato","base_url":"https://researchcommons.waikato.ac.nz/server/oai/request"},"display":{"title":"Structural and electrical characterisation of some ABO₃ perovskites","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 241.68ų at 1450 °C, 15%Mg concentration. In summary, Mg-doped LaFeO₃ produced a single phase material in the range 0-20 mol% Mg as observed from X-ray diffraction. However, a small amount of impurities in each of the samples was observed, containing La₂O₃ and La₂MgOₓ. The presence of the impurities suggested that an extra calcination step be included in the processing of the material. LaGdO₃ was fabricated using reverse strike co-precipitation method and sintered at temperature of 1350, 1400 and 1450 °C. X-ray diffraction showed the presence of a single monoclinic phase. Raman spectroscopy showed a spectrum similar for that reported for the B-type rare earth oxide Gd₂O₃ and the band positions of the low temperature Raman spectrum were assigned in comparison with this. A total of 18 bands were identified. Intense broad profile in the region 1000-2000 cm⁻¹ was observed for LaGdO₃, likely due to fluorescent/luminescent bands. The acceptor-doped perovskite proton conductor SrCe₁₋ₓYₓO₃₋δ (x=0.025 to 0.20, δ = x/2) was prepared and characterised using X-ray diffraction and AC impedance spectroscopy, and the effect of the yttrium dopant concentration on structure and electrical properties has been investigated. X-ray diffraction studies showed a decrease in lattice volume with increasing yttrium content. Electrical conductivity studies were made as a function of oxygen partial pressure, and a partial pressure of water vapour of 0.001 and 0.01 atm. The total conductivity was separated into different components by fitting procedures and regions of ionic and p-type conduction were identified. At 800°C, and at the water vapour partial pressure of 0.01 atm, the ionic conductivity showed a maximum at a doping level of x = 0.10, reaching a value of 5 mS/cm. The conductivity component appearing at low oxygen partial pressure, which according to recent studies may be regarded as protonic rather than n-type, decreased with doping, while the p-type component at high oxygen partial pressure increased.","abstract_html":"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 241.68ų at 1450 °C, 15%Mg concentration. In summary, Mg-doped LaFeO₃ produced a single phase material in the range 0-20 mol% Mg as observed from X-ray diffraction. However, a small amount of impurities in each of the samples was observed, containing La₂O₃ and La₂MgOₓ. The presence of the impurities suggested that an extra calcination step be included in the processing of the material. LaGdO₃ was fabricated using reverse strike co-precipitation method and sintered at temperature of 1350, 1400 and 1450 °C. X-ray diffraction showed the presence of a single monoclinic phase. Raman spectroscopy showed a spectrum similar for that reported for the B-type rare earth oxide Gd₂O₃ and the band positions of the low temperature Raman spectrum were assigned in comparison with this. A total of 18 bands were identified. Intense broad profile in the region 1000-2000 cm⁻¹ was observed for LaGdO₃, likely due to fluorescent/luminescent bands. The acceptor-doped perovskite proton conductor SrCe₁₋ₓYₓO₃₋δ (x=0.025 to 0.20, δ = x/2) was prepared and characterised using X-ray diffraction and AC impedance spectroscopy, and the effect of the yttrium dopant concentration on structure and electrical properties has been investigated. X-ray diffraction studies showed a decrease in lattice volume with increasing yttrium content. Electrical conductivity studies were made as a function of oxygen partial pressure, and a partial pressure of water vapour of 0.001 and 0.01 atm. The total conductivity was separated into different components by fitting procedures and regions of ionic and p-type conduction were identified. At 800°C, and at the water vapour partial pressure of 0.01 atm, the ionic conductivity showed a maximum at a doping level of x = 0.10, reaching a value of 5 mS/cm. The conductivity component appearing at low oxygen partial pressure, which according to recent studies may be regarded as protonic rather than n-type, decreased with doping, while the p-type component at high oxygen partial pressure increased.","abstract_has_math":false,"creators":["Phillips, Roslyn June"],"institution":"The University of Waikato","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Sammes, Nigel"],"committee_chairs":[],"committee_members":[],"year":1999,"date_issued":"1999","date_published":"1999","updated_at":"2026-07-24T05:57:52Z","subjects":[],"languages":[],"rights":["All items in Research Commons are provided for private study and research purposes and are protected by copyright with all rights reserved unless otherwise indicated."],"rights_urls":["https://researchcommons.waikato.ac.nz/bitstreams/45b20647-d12b-4950-9cb0-c1d24bd1c01b/download"],"identifier_entries":[]},"links":{"outbound_url":null,"outbound_label":null,"outbound_source":null},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Sammes, Nigel"]},{"key":"dc:creator","label":"Author","values":["Phillips, Roslyn June"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.issued","label":"Date","values":["1999"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["The University of Waikato"]},{"key":"dc:relation.isreferencedby","label":"Dc Relation Isreferencedby","values":["https://hdl.handle.net/10289/15454"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["https://researchcommons.waikato.ac.nz/bitstreams/45b20647-d12b-4950-9cb0-c1d24bd1c01b/download","All items in Research Commons are provided for private study and research purposes and are protected by copyright with all rights reserved unless otherwise indicated."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://researchcommons.waikato.ac.nz/bitstreams/f275dea2-8574-45a4-87c3-a6322882c48a/download"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["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 241.68ų at 1450 °C, 15%Mg concentration. In summary, Mg-doped LaFeO₃ produced a single phase material in the range 0-20 mol% Mg as observed from X-ray diffraction. However, a small amount of impurities in each of the samples was observed, containing La₂O₃ and La₂MgOₓ. The presence of the impurities suggested that an extra calcination step be included in the processing of the material. LaGdO₃ was fabricated using reverse strike co-precipitation method and sintered at temperature of 1350, 1400 and 1450 °C. X-ray diffraction showed the presence of a single monoclinic phase. Raman spectroscopy showed a spectrum similar for that reported for the B-type rare earth oxide Gd₂O₃ and the band positions of the low temperature Raman spectrum were assigned in comparison with this. A total of 18 bands were identified. Intense broad profile in the region 1000-2000 cm⁻¹ was observed for LaGdO₃, likely due to fluorescent/luminescent bands. The acceptor-doped perovskite proton conductor SrCe₁₋ₓYₓO₃₋δ (x=0.025 to 0.20, δ = x/2) was prepared and characterised using X-ray diffraction and AC impedance spectroscopy, and the effect of the yttrium dopant concentration on structure and electrical properties has been investigated. X-ray diffraction studies showed a decrease in lattice volume with increasing yttrium content. Electrical conductivity studies were made as a function of oxygen partial pressure, and a partial pressure of water vapour of 0.001 and 0.01 atm. The total conductivity was separated into different components by fitting procedures and regions of ionic and p-type conduction were identified. At 800°C, and at the water vapour partial pressure of 0.01 atm, the ionic conductivity showed a maximum at a doping level of x = 0.10, reaching a value of 5 mS/cm. The conductivity component appearing at low oxygen partial pressure, which according to recent studies may be regarded as protonic rather than n-type, decreased with doping, while the p-type component at high oxygen partial pressure increased."]},{"key":"dc:format.checksum.md5","label":"Dc Format Checksum Md5","values":["604a07b7318e0b3a0103240c7807ff93","e14202ab27e47ddb00d33097327ba050","3ed01eb75c00b5156ffd5527114487a2"]},{"key":"dc:title","label":"Title","values":["Structural and electrical characterisation of some ABO₃ perovskites"]}]}],"canonical_facts":{"dc:contributor.advisor":["Sammes, Nigel"],"dc:creator":["Phillips, Roslyn June"],"dc:date.issued":["1999"],"dc:description.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 241.68ų at 1450 °C, 15%Mg concentration. In summary, Mg-doped LaFeO₃ produced a single phase material in the range 0-20 mol% Mg as observed from X-ray diffraction. However, a small amount of impurities in each of the samples was observed, containing La₂O₃ and La₂MgOₓ. The presence of the impurities suggested that an extra calcination step be included in the processing of the material. LaGdO₃ was fabricated using reverse strike co-precipitation method and sintered at temperature of 1350, 1400 and 1450 °C. X-ray diffraction showed the presence of a single monoclinic phase. Raman spectroscopy showed a spectrum similar for that reported for the B-type rare earth oxide Gd₂O₃ and the band positions of the low temperature Raman spectrum were assigned in comparison with this. A total of 18 bands were identified. Intense broad profile in the region 1000-2000 cm⁻¹ was observed for LaGdO₃, likely due to fluorescent/luminescent bands. The acceptor-doped perovskite proton conductor SrCe₁₋ₓYₓO₃₋δ (x=0.025 to 0.20, δ = x/2) was prepared and characterised using X-ray diffraction and AC impedance spectroscopy, and the effect of the yttrium dopant concentration on structure and electrical properties has been investigated. X-ray diffraction studies showed a decrease in lattice volume with increasing yttrium content. Electrical conductivity studies were made as a function of oxygen partial pressure, and a partial pressure of water vapour of 0.001 and 0.01 atm. The total conductivity was separated into different components by fitting procedures and regions of ionic and p-type conduction were identified. At 800°C, and at the water vapour partial pressure of 0.01 atm, the ionic conductivity showed a maximum at a doping level of x = 0.10, reaching a value of 5 mS/cm. The conductivity component appearing at low oxygen partial pressure, which according to recent studies may be regarded as protonic rather than n-type, decreased with doping, while the p-type component at high oxygen partial pressure increased."],"dc:format.checksum.md5":["604a07b7318e0b3a0103240c7807ff93","e14202ab27e47ddb00d33097327ba050","3ed01eb75c00b5156ffd5527114487a2"],"dc:identifier.uri":["https://researchcommons.waikato.ac.nz/bitstreams/f275dea2-8574-45a4-87c3-a6322882c48a/download"],"dc:publisher.institution":["The University of Waikato"],"dc:relation.isreferencedby":["https://hdl.handle.net/10289/15454"],"dc:rights":["https://researchcommons.waikato.ac.nz/bitstreams/45b20647-d12b-4950-9cb0-c1d24bd1c01b/download","All items in Research Commons are provided for private study and research purposes and are protected by copyright with all rights reserved unless otherwise indicated."],"dc:title":["Structural and electrical characterisation of some ABO₃ perovskites"],"dc:type":["Thesis"]},"updated_at":"2026-07-24T05:57:52Z"}