Electrical conductivity of La 1−x Ca x FeO 3−δ solid solutions

Andoulsi, Refka; Horchani−Naifer, Karima; Férid, Mokhtar

doi:10.1016/j.ceramint.2013.01.085

Cited by 64 publications

(30 citation statements)

References 23 publications

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“…LaFeO 3 at nanoscale shows superior properties such as higher surface area, better catalytic activity and sensing properties as compared to bulk LaFeO 3 due to quantum size effect [9]. Interestingly, the perovskite structure of LaFeO 3 is able to accommodate a large variety of dopant ions, where the properties of the final product can be finely tuned and controlled depending on the nature and content of the dopant [10,11]. The choice of method adopted for synthesis along with doping level in LaFeO 3 have been found to bring remarkable changes in the various physico-chemical properties.…”

Section: Introductionmentioning

confidence: 98%

Effect of different synthetic routes on the structural, morphological and magnetic properties of Ce doped LaFeO3 nanoparticles

Shikha

Kang

Randhawa

2015

Journal of Alloys and Compounds

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Section: Introductionmentioning

confidence: 98%

Effect of different synthetic routes on the structural, morphological and magnetic properties of Ce doped LaFeO3 nanoparticles

Shikha

Kang

Randhawa

2015

Journal of Alloys and Compounds

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“…9 Recent short-term investigations under laboratory conditions in pure O 2 -Ar atmospheres showed that perovskites from the series (La,Ca)FeO 3-δ show a high activity toward oxygen reduction, as well as good electronic and ionic conductivities. [24][25][26][27][28][29][30][31] However, the long-term stability of (La,Ca)FeO 3-δ , which is a key issue for the application of these materials as air electrodes in SOFCs and SOECs, has yet to be demonstrated, especially under application-relevant conditions in atmospheres containing contaminants.…”

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confidence: 99%

Impact of SO₂on the Oxygen Exchange Kinetics of the Promising SOFC/SOEC Air Electrode Material La_0.8Ca_0.2FeO_3-δ

Berger

Bucher

Gspan

et al. 2017

J. Electrochem. Soc.

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The mass and charge transport properties of La 0.8 Ca 0.2 FeO 3-δ (LCF82) were determined at 600-800 • C and pO 2 = 0.1 bar. The electronic conductivity is in the range of 112 S cm −1 at 700 • C. The chemical surface exchange coefficient (k chem ) and the chemical diffusion coefficient of oxygen (D chem ) were measured. LCF82 shows exceptionally fast oxygen exchange kinetics in pure O 2 -Ar at 700 • C. Long-term measurements at 700 • C in pure O 2 -Ar showed an excellent stability of the kinetic parameters during 1000 h. However, when 2 ppm of sulfur dioxide were added, k chem decreased by a factor of 40 within the first 24 h. After further 1000 h, the total decrease in k chem amounted to two orders of magnitude. Post-test analyses of LCF82 were performed by SEM-EDXS, XPS, and STEM. Ca-enrichment and La-/Fe-depletion of the LCF82 surface occurred during the first 1000 h without SO 2 . At the surface of the sample exposed to 2 ppm SO 2 for additional 1000 h, CaSO 4 crystals with diameters of 1-2 μm and an underlying layer of Fe 2 O 3 (thickness approx. 300-450 nm) were found. Remarkably, LCF82 shows faster oxygen exchange kinetics than La 0.6 Sr 0.4 CoO 3-δ even in the degraded state. Therefore, LCF82 is suggested as a promising material for SOFC and SOEC air electrodes.

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“…The conductivity trends during heating and cooling cycles and the Arrhenius plots for both materials are shown in Figure 2.11. The plot in Figure 2.11b was used for fitting with the Arrhenius equation for thermally activated conductivity, [49][50][51] which helped to find the activation energy of total conductivity.…”

Section: Electrical Propertiesmentioning

confidence: 99%

“…The change in conductivity as a function of temperature can be described using the Arrhenius equation for thermally activated conductivity: [49][50][51] = − ( 19 ) where σ° is a pre-exponential factor and a characteristic of the material. Ea, K, and T are the activation energy for the electrical conductivity, Boltzmann constant, and absolute temperature, respectively.…”

Section: Electrical Propertiesmentioning

confidence: 99%

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Oxygen deficient perovskites: effect of structure on electrical conductivity, magnetism and electrocatalytic activity.

Hona¹

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Oxygen evolution reaction …………………………………………....19 CHAPTER 2. TRANSFORMATION OF STRUCTURE, ELECTRICAL CONDUCTIVITY AND MAGNETISM IN AA'Fe2O6-δ, A=Sr, Ca and A'= Sr..…... 21 Introduction ………………………………………………………………….. 21 Experimental ……... …………………………………………………………. 23 Results and discussion ………………………………………………………. 25 Crystal structure ……………………………………………………... 25 Magnetic structure …………………………………………………… 33 Electrical Properties ………………………………………………..… 36 Conclusion ………………………………………………………………...…. 43 CHAPTER 3. UNRAVELING THE ROLE OF STRUCTURAL ORDER IN TRANSFORMATION OF ELECTRICAL CONDUCTIVITY IN Ca2FeCoO6-δ, CaSrFeCoO6-δ and Sr2FeCoO6-δ …………………………………………………..….. 44 ix Introduction ………………………………………………………………...…. 44 Experimental ………………………………………………………………..…. 46 Results and discussion …………………………………….…………………. 48 Crystal structure ………………………………………….…………… 48 X-ray photoelectron spectroscopy …………………………………… 61 Electrical conductivities ……………………………………...………. 65 Conclusion …………………………………………………………………….. 73 CHAPTER 4. MAGNETIC STRIUCTURE OF CaSrFeCoO5 ………………..……… 75 Introduction …………………………………………………………….……….75 Experimental section ……………………………………………….………….. 77 Results and discussion ………………………………………………………….……. 78 Conclusion ……………………………………………………………….…………… 86 CHAPTER 5. ELECTRICAL PROPERTIES OF ORDERED OXYGEN-DEFICIENT PEROVSKITE Ca2Fe0.5Ga1.5O5…………..…..……………………………………….. 87 Introduction …………………………………………….……………………. 87 Materials and methods ………………………………….……………………. 90 Results and discussion ……………………………………...……….…………91 Crystal structure …………………………………………….….……… 91 x Electrical properties ………………………………..………….……… 94 Conclusion ……………………………………………..…………..…………. 99 CHAPTER 6. ENHANCED ELECTRICAL PROPERTIES OIN BaSrFe2O6-δ (δ=0.5): A DISORDERED DEFECT-PEROVSKITE………………………..………………..…. 100 Introduction …………………………………………………….…………… 100 Experimental……… ………………………………………..……………….. 102 Results and discussion …………………………………………..…………… 103 Crystal structure …………………………………………………...…. 103 Magnetic properties ………………………………………...…………109 Electrical properties ………………………………………………….. 111 Conclusion ……………………………………………….………………….. 115 CHAPTER 7. CHARGE-TRANSPORT PROPERTIES OF Ca2FeGaO6-δ AND CaSrFeGaO6-δ: THE EFFECT OF DIFECT-ORDERED .……………………...…….. 117 Introduction ………………………………………………………………….. 117 Experimental …………………………………………….………………….. 120 Results and discussion ………………………………..……………………… 121 Crystal structure ……………………………………………….…….. 121 Microstructure and X-ray photoelectron spectroscopy studies…………125 Electrical properties ………………………………….………………. 127 Conclusion ………………………………………………………..…………. 133 xi CHAPTER 8. DISPARITY IN ELECTRICAL AND MAGNETIC PROPERTIES OF ISOSTRUCTURAL OXYGEN-DEFICIENT PEROVSKITES BaSrCo2O6-δ AND BaSrCoFeO6-δ ………..………….……………………………………………..…….. 134 Introduction ……………………………………………………….…………. 134 Experimental……… …………………………………….….………………… Results and discussion …………………………………….……...………….. Crystal structure and crystallite morphology …….………….………… X-ray photoelectron spectroscopy (XPS) and iodometric titration ….…141 Magnetic properties ……………………………………………....…… Electrical conductiviti...

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Electrical conductivity of La 1−x Ca x FeO 3−δ solid solutions

Cited by 64 publications

References 23 publications

Effect of different synthetic routes on the structural, morphological and magnetic properties of Ce doped LaFeO3 nanoparticles

Effect of different synthetic routes on the structural, morphological and magnetic properties of Ce doped LaFeO3 nanoparticles

Impact of SO₂on the Oxygen Exchange Kinetics of the Promising SOFC/SOEC Air Electrode Material La_0.8Ca_0.2FeO_3-δ

Oxygen deficient perovskites: effect of structure on electrical conductivity, magnetism and electrocatalytic activity.

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Electrical conductivity of La 1−x Ca x FeO 3−δ solid solutions

Cited by 64 publications

References 23 publications

Effect of different synthetic routes on the structural, morphological and magnetic properties of Ce doped LaFeO3 nanoparticles

Effect of different synthetic routes on the structural, morphological and magnetic properties of Ce doped LaFeO3 nanoparticles

Impact of SO2on the Oxygen Exchange Kinetics of the Promising SOFC/SOEC Air Electrode Material La0.8Ca0.2FeO3-δ

Oxygen deficient perovskites: effect of structure on electrical conductivity, magnetism and electrocatalytic activity.

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Impact of SO₂on the Oxygen Exchange Kinetics of the Promising SOFC/SOEC Air Electrode Material La_0.8Ca_0.2FeO_3-δ