Title Details

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 Electro‐optic Properties 293

9.7.1 Refractive Index Changes 293

9.7.2 Electro‐optic Phase Modulators 294

9.7.3 Electro‐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 Kröger–Vink Defect Notation 307

Index 309