Pyrochlore ceramics : properties, processing, and applications /

"Present-day interest in pyrochlore materials is immense. Academic and industrial researchers working with pyrochlore materials need a fundamental understanding of what pyrochlores are and their potential applications. Pyrochlore Ceramics: Properties, Processing, and Applications provides key k...

Full description

Bibliographic Details
Corporate Author:	ScienceDirect (Online service)
Other Authors:	Chowdhury, Anirban (Editor)
Format:	eBook
Language:	English
Published:	Amsterdam, Netherlands : Elsevier, 2022.
Series:	Elsevier series on advanced ceramic materials.
Subjects:	Oxide minerals. Ceramics. Oxydes (Minéraux) Céramique industrielle. ceramic (material) Ceramics Oxide minerals Electronic books.
Online Access:	Connect to the full text of this electronic book

Table of Contents:

Intro
Pyrochlore Ceramics: Properties, Processing, and Applications
Copyright
Dedication
Contents
List of contributors
Biographies
Preface
Section 1: Process and structure of pyrochlores
Chapter 1: Crystal chemistry and phase transitions in pyrochlore and related structures
1.1. Introduction
1.2. Fluorite supergroup
1.3. Pyrochlore supergroup
1.3.1. Pyrochlore group
1.3.2. Microlite group
1.3.3. Roméite group
1.3.4. Elsmoreite group
1.3.5. Unassigned members
1.3.6. Betafite group
1.4. Weberite group
1.5. Zirconolite group
1.6. Ingersonite
1.7. Murataite-(Y)
1.8. Pittongite
1.9. Phyllotungstite
1.10. Allendeite
Acknowledgments
References
Chapter 2: Crystal growth of magnetic pyrochlore oxides and their structure-property correlations
2.1. Introduction
2.2. Pyrochlore structure
2.3. Crystal growth of pyrochlores
2.3.1. Crystal growth techniques
2.3.1.1. Optical floating zone method
2.3.1.2. High-temperature solution growth method
2.3.2. Crystal growth of some specific pyrochlore families
2.3.2.1. Titanates
2.3.2.2. Zirconates
2.3.2.3. Molybdates
2.3.2.4. Iridates
2.4. Structure-property correlations
2.4.1. Titanates
2.4.1.1. Tb2Ti2O7
2.4.1.2. Dy2Ti2O7 and Ho2Ti2O7
2.4.1.3. Yb2Ti2O7
2.4.1.4. Sm2Ti2O7
2.4.2. Zirconates
2.4.2.1. Nd2Zr2O7
2.4.2.2. Pr2Zr2O7
2.4.2.3. Sm2Zr2O7
2.4.2.4. Dy2Zr2O7and Er2Zr2O7
2.4.3. Molybdates
2.4.4. Iridates
2.4.4.1. Specific difficulties in controlling the stoichiometry of pyrochlore iridates
2.4.4.2. Stuffing studies in the pyrochlore iridates
2.4.4.3. Doping studies in the pyrochlore iridates
Filling control
Bandwidth control
Miscellaneous doped sample
2.5. Conclusions and perspectives
Acknowledgments
References.
Chapter 3: Raman spectroscopy study of disorder phenomena and size effects in pyrochlores
3.1. Introduction
3.1.1. The A2B2O(1)6O(2) pyrochlore structure
3.1.2. Ionic radii and pyrochlore stability
3.2. The Raman spectrum of ordered pyrochlores
3.2.1. Group theory and mode assignment
3.2.2. Raman spectra of well-ordered pyrochlores (BTi, Sn)
3.2.3. Wavenumber and atomic displacement calculations
3.2.4. Other features of ordered-pyrochlore spectra
3.2.4.1. Second-order excitations
3.2.4.2. Anharmonic effects
3.2.4.3. Crystal field transitions
3.3. Disordered pyrochlores
3.3.1. Defect energetics and the pyrochlore to fluorite transition
3.3.2. Examples of Raman spectra of disordered pyrochlores
3.3.2.1. Positional disorder in R2B2O7 (BZr, Hf) compounds
3.3.2.2. Positional and chemical disorder in A-site solid solutions
3.3.2.3. Positional and chemical disorder in B-site solid solutions
3.3.2.4. Disorder-activated modes and relation with atomic distribution
3.3.2.5. Nonstoichiometric compounds
3.3.3. SRO domains
3.3.4. Disorder as a response to high-energy stimuli and nonequilibrium situations
3.3.4.1. High temperature
3.3.4.2. Irradiation
3.3.4.3. High pressure
3.3.4.4. Disorder and size-effects in as-grown materials
3.4. Summary and conclusions
References
Chapter 4: Effect of different fabrication avenues of pyrochlore ceramics toward order-disorder transitions
4.1. Introduction
4.2. Chemical synthesis techniques
4.2.1. Solid state method
4.2.2. Coprecipitation method
4.2.3. Sol-gel synthesis
4.2.4. Pechini method
4.2.5. Hydrothermal method/solvothermal synthesis
4.2.6. Molten salt synthesis method
4.2.7. Combustion method
4.3. Conclusions
Acknowledgments
References.
Chapter 5: Process-structure correlations in complex A2B2O7 systems: Nanoparticles and ceramics
5.1. Introduction
5.2. Order-disorder transition
5.3. Distinguishing defect fluorite and pyrochlore phases
5.4. Pyrochlores with different elemental systems
5.4.1. Pyrochlores containing cerium (Ce)
5.4.2. Zirconate pyrochlores
5.4.2.1. Lanthanum zirconate (La2Zr2O7)
5.4.2.2. Role of dopants in LZ system
5.4.2.3. Gadolinium zirconate (Gd2Zr2O7)
5.4.2.4. Neodymium zirconate (Nd2Zr2O7)
5.4.2.5. Yttrium zirconate (Y2Zr2O7)
5.4.2.6. Other zirconate pyrochlores
5.4.3. Hafnate pyrochlores
5.4.4. Stannate pyrochlores
5.4.5. Iridate pyrochlores
5.5. Sintering resistance of pyrochlores
5.6. High-entropy pyrochlore ceramics
5.7. Summary and conclusions
5.7.1. Structure and crystal chemistry of pyrochlores
5.7.2. Characterization issues with pyrochlore structures
5.7.3. Synthesis and processing of pyrochlores
5.7.4. Different families of pyrochlores
5.7.5. Pyrochlores for TBC applications
References
Section 2: Functional properties of pyrochlore systems
Chapter 6: Electrochemical properties of complex pyrochlores
6.1. Introduction
6.2. General aspects of pyrochlore-type oxide conductivity
6.3. Structural disordering. Defects. Oxygen migration pathways
6.4. Regulation of electrochemical behavior of oxide pyrochlores by doping
6.4.1. Doping into A-sites
6.4.2. Doping into B-sites
6.4.3. Doping into A- and B-sites
6.5. Electrochemical behavior of complex pyrochlores based on niobates, tantalates, antimoniate
6.6. Potential electrochemical applications of complex oxide pyrochlores
6.6.1. Potential cathodic and anodic materials (or electrode materials for SOFC) based on complex pyrochlores
6.6.2. Oxygen electrocatalysts
6.6.3. Proton conductivity.
6.7. Conclusions
References
Chapter 7: Ionic conductivity in materials with a pyrochlore structure
7.1. Introduction
7.2. Impedance instrumentation
7.3. Synthesis of pyrochlores
7.4. Conductivity of pyrochlores
7.4.1. Titanate pyrochlores
7.4.2. Zirconate pyrochlores
7.4.3. Hafnate and stannate pyrochlores
7.4.4. Niobate and tantalate pyrochlores
7.4.5. Molybdate pyrochlores
7.4.6. Conductivity of irradiated samples
7.4.7. Cationic conductivity in pyrochlores
7.4.8. Proton conductivity
7.5. Summary and future scope
References
Chapter 8: Nonferroelectric relaxor dielectric properties of pyrochlore phases
8.1. Introduction
8.2. Crystal structure
8.3. Ferroelectricity?
8.4. Dielectric relaxation
8.5. Conclusions
Acknowledgments
References
Chapter 9: Unusual magnetic properties of ternary Bi- and Ln-containing pyrochlores: From cooperative paramagnetism to
9.1. Introduction
9.1.1. Overview
9.1.2. Theoretical background, cooperative paramagnetism, frustration factor
9.1.3. Spin glass
9.1.4. Cluster glass
9.1.5. Reentrant spin glass
9.2. Experimental results
9.2.1. The Bi/Ln-Fe-Nb/Sb/Te-O (Ln=La, Pr) pyrochlores
9.2.2. The A-Mn-O (A=Tl, Y, In, Lu, or Ln and Bi-Mn/M-O (M=Nb, Sb) pyrochlores
9.2.3. The Ln/Bi-Ni/Co-Sb/Nb-O pyrochlores
9.2.4. The Ln/Bi-Cr-Sb-O (A=Tl, Y, In, and Lu) and Ln2CrTaO7 (Ln=Y, Sm, Gd) pyrochlores
9.3. Discussion
9.4. Conclusions
Acknowledgment
References
Chapter 10: Pyrochlores: Prospects as a photocatalyst for environmental and energy applications
10.1. Introduction
10.2. Pyrochlores
10.3. Pyrochlore composition, structure, and diversity
10.4. Properties of pyrochlore-type materials
10.5. Photocatalysis
10.5.1. Bandgap and defects
10.6. Photodegradation of organic pollutants.
10.7. Water splitting
10.8. CO2 reduction
10.9. Summary
References
Chapter 11: Photoluminescence in pyrochlore structures
11.1. Introduction
11.1.1. Luminescence
11.1.2. Basics of luminescence
11.1.3. Energy transfer
11.1.4. Applications
11.1.4.1. LED applications
11.1.4.2. Temperature sensors
11.1.4.3. Biomedical applications
11.1.4.4. Agriculture applications
11.2. Photoluminescence in pyrochlore structures
11.2.1. Importance of host matrix for photoluminescence
11.2.2. Pyrochlore structure as a host for photoluminescence
11.2.3. Photoluminescence studies of Eu3+-activated binary type pyrochlore systems: RE2M2O7(RE=Y, La, Gd, Lu
M=Ti, Zr, H ...
11.2.3.1. Eu3+ ion activator
11.2.3.2. Effects of A- and B-site cations
11.2.3.3. Structural transformation
11.2.3.4. Particle size control
11.2.3.5. Defect concentration control
11.2.4. Maneuverability of photoluminescence in quaternary Pyrochlore system: CaREMNbO7
RE=Y, La, Gd
M=Sn, Ti
11.2.4.1. Distortion factor
11.2.4.2. Doping effect
11.2.4.3. Role of electronegativity of cations
11.2.4.4. Order/disorder control
11.2.5. Photoluminescence studies in displaced pyrochlore
11.3. Conclusions and future outlook
References
Section 3: Diverse applications of pyrochlore materials
Chapter 12: Transparent ceramics based on pyrochlores
12.1. Introduction
12.2. Fabrication of transparent ceramics based on pyrochlores
12.2.1. Synthesis methods of pyrochlore powders for transparent ceramics
12.2.2. Sintering techniques for transparent ceramics based on pyrochlores
12.3. Transparent ceramic materials based on pyrochlores
12.3.1. A2B2O7 pyrochlores and A-site substituted A2B2O7 pyrochlores
12.3.1.1. Titanate compounds
12.3.1.2. Zirconate compounds
12.3.1.3. Hafnate compounds.