Perovskites

Uniquely describes both the crystallography and properties of perovskite related materials.
* Practical applications in solar cells, microelectronics and telecommunications
* Interdisciplinary topic drawing on materials science, chemistry, physics, and geology
* Contains problems and answers to enhance knowledge retention

Preface xi
1 The ABX3 Perovskite Structure 1
1. 1 Perovskites 1
1. 2 The Cubic Perovskite Structure: SrTiO3 4
1. 3 The Goldschmidt Tolerance Factor 6
1. 4 ABX3 Perovskite Structure Variants 11
1. 5 Cation Displacement: BaTiO3 as an Example 12
1. 6 Jahn-Teller Octahedral Distortion: KCuF3 as an Example 16
1. 7 Octahedral Tilting 19
1. 7. 1 Tilt Descriptions 19
1. 7. 2 Trigonal Symmetry: LaAlO3 as an Example 24
1. 7. 3 Orthorhombic Symmetry: GdFeO3 and CaTiO3 as Examples 26
1. 8 Symmetry Relationships 30
1. 9 Hybrid Organic-Inorganic Perovskites 33
1. 10 Antiperovskites 34
1. 10. 1 Cubic and Related Structures 34
1. 10. 2 Other Structures 36
1. 11 Structure Field Maps 36
1. 12 Theoretical Calculations 38
References 40
Further Reading 40
2 ABX3-Related Structures 42
2. 1 Double Perovskites and Related Ordered Structures 42
2. 1. 1 Rock Salt Ordered Double Perovskites 42
2. 1. 2 Other Ordered Perovskites 45
2. 1. 3 AA 3B4O12 Related Phases 48
2. 2 Anion Substituted Perovskites 51
2. 2. 1 Nitrides and Oxynitrides 51
2. 2. 2 Oxyfluorides 53
2. 3 A Site Deficient Perovskite Structures 54
2. 3. 1 ReO3, WO3 and Related Structures 54
2. 3. 2 Perovskite Tungsten Bronzes 55
2. 3. 3 A Site Deficient Titanates, Niobates and Tantalates 55
2. 4 Anion Deficient Phases Containing Tetrahedra 57
2. 4. 1 Brownmillerites 57
2. 4. 2 Brownmillerite Microstructures 62
2. 4. 3 Temperature Variation and Disorder 63
2. 4. 4 B Site Doped Brownmillerite Phases 64
2. 4. 5 B Site Doping and Oxygen Pressure 65
2. 4. 6 A Site Doped Brownmillerite Phases 65
2. 4. 7 Brownmillerite Related Phases 66
2. 5 Anion Deficient Phases Containing Square Pyramids 69
2. 5. 1 Manganites 69
2. 5. 2 SrFeO2. 5 and Related Phases 71
2. 5. 3 Cobaltite Related Phases 73
2. 6 Point Defects, Microdomains and Modulated Phases 74
Further Reading 78
3 Hexagonal Perovskite-Related Structures 79
3. 1 The BaNiO3 Structure 79
3. 2 BaNiO3 Related Phases Containing Trigonal Prisms 81
3. 2. 1 Commensurate Structures 81
3. 2. 2 Modulated Structures 89
3. 3 Perovskites with Mixed Hexagonal/Cubic Packing: Nomenclature 92
3. 4 Perovskites with Mixed Hexagonal/Cubic Packing: Stacking Sequences 95
3. 5 Hexagonal Perovskites with chq and cph Stacking 98
3. 5. 1 (chq) Structures 98
3. 5. 2 (cph) Structures 99
3. 5. 3 cphq Intergrowth Structures 104
3. 6 Hexagonal Perovskites with cphh Stacking 106
3. 6. 1 (cc. . . chh) AnBnO3n Structures 107
3. 6. 2 (cc. . . chh) AnBn 1O3n Structures 108
3. 6. 3 (hhcc. . . chhcc. . . c) Intergrowth Phases 110
3. 6. 4 (cc. . . ch) AnBn 1O3n Shift and Twinned Phases 112
3. 7 Anion Deficient Phases Containing BaO2 (c ) Layers 112
3. 7. 1 (c. . . c . . . ch) Structures 113
3. 7. 2 (c. . . c . . . chh) Structures 113
3. 7. 3 (c. . . c . . . chhh) Structures 115
3. 8 Anion Deficient Phases with BaOX Layers 117
3. 8. 1 (h ) Layers 117
3. 8. 2 (c c ) Layers 119
3. 9 Sr4Mn3O10 and Ba6Mn5O16 120
3. 10 Temperature and Pressure Variation 120
Reference 122
Further Reading 122
4 Modular Structures 123
4. 1 K2NiF4 (A2BX4) and Ruddlesden-Popper Phases 123
4. 1. 1 The K2NiF4 (T or T/O) Structure 123
4. 1. 2 Ruddlesden-Popper Phases 127
4. 2 The Nd2CuO4 (T ) and T* Structures 129
4. 3 Dion-Jacobson and Related Phases 131
4. 4 Aurivillius Phases 134
4. 5 The Ca2Nb2O7 Related Phases 136
4. 6 Cuprate Superconductors and Related Phases 138
4. 6. 1 La2CuO4, Nd2CuO4 and YBa2Cu3O7 139
4. 6. 2 Layered Perovskite Structures 141
4. 6. 3 Structures Related to the Layered Cuprate Phases 142
4. 7 Composition Variation 146
4. 8 Intercalation and Exfoliation 151
Further Reading 154
5 Diffusion and Ionic Conductivity 156
5. 1 Diffusion 156
5. 2 Ionic Conductivity 159
5. 3 Proton Conductivity 162
5. 4 Oxygen Pressure Dependence and Electronic Conductivity 165
5. 5 Oxide Ion Mixed Conductors 167
5. 6 Proton Mixed Conductors 169
5. 7 Solid Oxide Fuel Cells 172
References 174
Further Reading 174
6 Dielectric Properties 176
6. 1 Insulating Perovskites 176
6. 2 Dielectric Perovskites 178
6. 2. 1 General Properties 178
6. 2. 2 Colossal Dielectric Constant Materials 181
6. 3 Ferroelectric/Piezoelectric Perovskites 182
6. 3. 1 Spontaneous Polarisation and Domains 182
6. 3. 2 Ferroelectric Domain Switching 185
6. 3. 3 Ferroelectric Hysteresis Loops 188
6. 3. 4 Temperature Dependence of Ferroelectricity 189
6. 3. 5 Pyroelectrics, Piezoelectrics and Crystal Symmetry 191
6. 3. 6 Strain versus Electric Field Loops 192
6. 4 The Development of Ferroelectric/Piezoelectric Ceramic Bodies 193
6. 4. 1 Ceramic Piezoelectrics 193
6. 4. 2 Electrostriction 195
6. 5 Antiferroelectrics 196
6. 6 Ferrielectrics 199
6. 7 Relaxor Ferroelectrics 200
6. 7. 1 Macroscopic Characteristics of Relaxor Ferroelectrics 200
6. 7. 2 Microstructures of Relaxor Ferroelectrics 202
6. 8 Improper Ferroelectricity 206
6. 9 Doping and Modification of Properties 208
6. 10 Nanoparticles and Thin Films 212
References 215
Further Reading 215
7 Magnetic Properties 217
7. 1 Magnetism in Perovskites 217
7. 2 Paramagnetic Perovskites 219
7. 3 Antiferromagnetic Perovskites 222
7. 3. 1 Cubic Perovskite Related Structures 222
7. 3. 2 Hexagonal Perovskites 229
7. 4 Ferromagnetic Perovskites 233
7. 5 Ferrimagnetic Perovskites 236
7. 6 Spin Glass Behaviour 237
7. 7 Canted Spins and Other Magnetic Ordering 238
7. 8 Thin Films 240
7. 9 Nanoparticles 243
7. 10 Multiferroic Perovskites 243
References 246
Further Reading 246
8 Electronic Conductivity 247
8. 1 Perovskite Band Structure: Metallic Perovskites 247
8. 2 Metal-Insulator Transitions 250
8. 2. 1 Titanates and Related Phases 250
8. 2. 2 LnNiO3 252
8. 2. 3 Lanthanoid Manganites 253
8. 2. 4 Lanthanoid Cobaltites 254
8. 2. 5 (Sr, Ca)2RuO4 and Ca2Ru1 xCrxO4 255
8. 2. 6 NaOsO3 256
8. 3 Perovskite Superconductors 257
8. 4 Cuprate High Temperature Superconductors 258
8. 4. 1 Overview 258
8. 4. 2 Lanthanum Cuprate, La2CuO4 259
8. 4. 3 Neodymium Cuprate, Nd2CuO4 260
8. 4. 4 Yttrium Barium Copper Oxide, YBa2Cu3O7 261
8. 4. 5 Perovskite Related Structures and Series 263
8. 4. 6 The Generic Superconductivity Phase Diagram 263
8. 4. 7 Defects and Conductivity 265
8. 5 Spin Polarisation and Half Metals 267
8. 6 Charge Ordering and Orbital Ordering 268
8. 7 Magnetoresistance 270
8. 7. 1 Collosal Magnetoresistance (CMR) in Manganites 270
8. 7. 2 Low Field Magnetoresistance 272
8. 8 Semiconductivity in Perovskites 272
8. 9 Thin Films and Surface Conductivity 275
References 275
Further Reading 275
9 Thermal and Optical Properties 277
9. 1 Thermal Expansion 277
9. 1. 1 Normal Thermal Expansion 277
9. 1. 2 Thermal Contraction 280
9. 1. 3 Zero Thermal Expansion Materials 283
9. 2 Thermoelectric Properties 284
9. 3 The Magnetocaloric Effect 287
9. 4 The Pyroelectric and Electrocaloric Effect 288
9. 5 Transparency 289
9. 6 Electrochromic Films 291
9. 7 Electrö optic Properties 293
9. 7. 1 Refractive Index Changes 293
9. 7. 2 Electrö optic Phase Modulators 294
9. 7. 3 Electrö optic Intensity Modulators 296
9. 7. 4 Ceramic Modulators 299
9. 8 Perovskite Solar Cells 299
Reference 302
Further Reading 302
Appendix A The Bond Valence Model for Perovskites 303
Appendix B Summary of the Krö ger-Vink Defect Notation 307
Index 309