Magnetic Resonance of Phase Transitions (eBook)

Front Cover 1
Magnetic Resonance of Phase Transitions 4
Copyright Page 5
Table of Contents 6
List of Contributors 8
Preface 10
Chapter 1. Basic Concepts of Structural Phase Transitions 12
I. Introduction 12
II. Macroscopic Theory 18
III. Microscopic Theories 21
IV. Experimental Approaches 31
References 33
Chapter 2. Basic Concepts of Magnetic Resonance 36
I. Introduction 37
II. Fundamentals 37
III. Nuclear Magnetic Resonance 47
IV. Nuclear Quadrupole Resonance 54
V. Electron Spin Resonance 57
VI. M.ssbauer Resonance 66
VII. Relaxation Measurements 72
References 86
Chapter 3. NMR and NQR in Fluids, Paramagnets, and Crystals 90
I. Introduction 90
II. Static and Time-Dependent Critical Phenomena 94
III. The NMR and NQR Approach 100
IV. NMR near the Critical Point in Fluids 108
V. NMR in the Paramagnetic Phase and near the Ordering Temperature 112
VI. NMR and NQR near Structural Phase Transitions 129
References 175
Chapter 4. NMR of Liquid Crystals 182
I. Introduction 183
II. Motional Averaging 196
III. Orientational Order 210
IV. Spin–Lattice Relaxation in Thermotropic Liquid Crystals 241
Appendix A Spherical Harmonics and Their Transformations 250
References 254
Chapter 5. Magnetic Resonance Studies of Proton Dynamics in KDP Type Ferroelectrics 258
I. Introduction 259
II. The Pseudo-Spin Model and the Soft Mode Dynamics 260
III. The Polarization Fluctuation Spectrum and the Central Peak 263
IV. Condensing Modes 269
V. Order Parameter and Shape of the O—H---O Hydrogen Bond Potential 272
VI. Short-Range Correlations of Proton Motion 276
VII. Fluctuations at Cationic Sites 281
VIII. Soft Mode Dynamics 283
IX. Central Peak Phenomena 289
X. Conclusions 300
References 300
Chapter 6. EPR of Transition Ions as a Probe of Structural Changes 302
I. Introduction 303
II. Transition Ions 304
III. Nature of Structural Phase Transitions 311
IV. Effect of Phase Transitions on EPR Data 313
V. Ferroelectrics 315
VI. Nonpolar Phase Transitions 326
VII. Magnetic Phase Transitions 334
VIII. Summary 337
References 338
Chapter 7. M.ssbauer Studies 342
I. Introduction 343
II. Basics of M.ssbauer Spectroscopy 344
III. Magnetic Phase Transitions 350
IV. Structual Phase Transitions 366
V. Metal-Nonmetal Transitions 382
VI. High-Spin–Low-Spin Transitions 384
VII. Other Phase Transitions 386
VIII. Conclusions 387
References 388
Index 394