Planes / Mañosa / Saxena Magnetism and Structure in Functional Materials

1. Auflage 2010
ISBN: 978-3-540-31631-2
Verlag: Springer Berlin Heidelberg
Format: PDF
Kopierschutz: 1 - PDF Watermark

E-Book, Englisch, Band 79, 254 Seiten

Reihe: Springer Series in Materials Science

Magnetism and Structure in Functional Materials addresses three distinct but related topics: (i) magnetoelastic materials such as magnetic martensites and magnetic shape memory alloys, (ii) the magnetocaloric effect related to magnetostructural transitions, and (iii) colossal magnetoresistance (CMR) and related manganites. The goal is to identify common underlying principles in these classes of materials that are relevant for optimizing various functionalities. The emergence of apparently different magnetic/structural phenomena in disparate classes of materials clearly points to a need for common concepts in order to achieve a broader understanding of the interplay between magnetism and structure in this general class of new functional materials exhibiting ever more complex microstructure and function. The topic is interdisciplinary in nature and the contributors correspondingly include physicists, materials scientists and engineers. Likewise the book will appeal to scientists from all these areas.

Autoren/Hrsg.

Planes, Antoni

Mañosa, Lluís

Saxena, Avadh

Inhaltsverzeichnis

1;Preface;7
2;Contents;9
3;List of Contributors;14
4;1 Complex Functional Materials;17
5;2 Spin, Charge, and Lattice Coupling in Multiferroic Materials;19
5.1;2.1 Introduction;19
5.2;2.2 Order Parameters and Multiferroics;21
5.3;2.3 Strain Tensor and Elastic Compatibility;22
5.4;2.4 Inhomogeneities in Ferroelastics;29
5.5;2.5 Inhomogeneities in Multiferroic Oxides;32
5.6;2.6 Charge and Spin as Local Stresses and Transition Temperatures;34
5.7;2.7 Summary and Further Work;37
5.8;References;38
6;3 Disorder in Magnetic and Structural Transitions: Pretransitional Phenomena and Kinetics;43
6.1;3.1 Introduction;43
6.2;3.2 Disorder Distribution;44
6.3;3.3 Transition Kinetics;53
6.4;3.4 Conclusion;61
6.5;References;62
7;4 Huge Magnetoresistance in Association with Strong Magnetoelastic Effects;65
7.1;4.1 Introduction;65
7.2;4.2 Magnetic–Crystallographic Transformations;66
7.3;4.3 Moment Instabilities and Spin Fluctuations;69
7.4;4.4 Metal–Insulator Transitions;73
7.5;4.5 Charge/Orbital Instabilities;81
7.6;4.6 Conclusion;86
7.7;References;87
8;5 Interplay of Spin, Charge, and Lattice in CMR Manganites and HTSC Cuprates;91
8.1;5.1 Introduction;91
8.2;5.2 Stability of Polaronic Phase in the CMR Manganites;92
8.3;5.3 Stability of Spin–Charge Stripes in the Cuprates;99
8.4;5.4 Electron–Phonon Coupling and Mechanism of Superconductivity in the Cuprates;100
8.5;5.5 Conclusions;105
8.6;References;106
9;6 Neutron Scattering Studies of Anomalous Phonon Behavior in Functional Materials;109
9.1;6.1 Introduction;109
9.2;6.2 Neutron Scattering;110
9.3;6.3 Phonon Anomalies;111
9.4;6.4 Phonon Anomalies in the Manganites;115
9.5;6.5 Phonon Anomalies in High Temperature Superconductors;116
9.6;6.6 Ferromagnetic Shape Memory Alloys;118
9.7;6.7 Summary;126
9.8;References;127
10;7 The Structures and Transformation Mechanism in the Ferromagnetic Shape Memory Alloy Ni2MnGa;129
10.1;7.1 Introduction;129
10.2;7.2 The Crystal Structure of the Cubic Austenite Phase;129
10.3;7.3 Bulk Magnetic Properties;132
10.4;7.4 Spin Dynamics;134
10.5;7.5 Paramagnetic Response;134
10.6;7.6 Inelastic Neutron Scattering;135
10.7;7.7 Neutron Diffraction;137
10.8;7.8 Pre-Martenstic Phase;138
10.9;7.9 The Martensitic Phase;142
10.10;7.10 Structural and Magnetic Phase Diagram;143
10.11;7.11 Mechanism;145
10.12;7.12 Martensitic Twinning in Ni2MnGa;146
10.13;7.13 Non Stoichiometric Samples;149
10.14;7.14 Electron Concentration;151
10.15;7.15 Polarised Neutron Scattering;152
10.16;7.16 Conclusion;153
10.17;References;154
11;8 Imaging Techniques in Magnetoelastic Materials;157
11.1;8.1 Introduction;157
11.2;8.2 Lorentz Image Formation Theory;157
11.3;8.3 Applications of LTEM to Ferromagnetic Shape Memory Alloys;164
11.4;8.4 Summary;172
11.5;References;172
12;9 A Way to Search for Multiferroic Materials with "Unlikely” Combinations of Physical Properties;175
12.1;9.1 Introduction;175
12.2;9.2 Single Phase Multiferroics;176
12.3;9.3 Basic Idea;176
12.4;9.4 Lattice Parameter Sensitivity;177
12.5;9.5 What Makes Big First Order Phase Transformations Reversible?;178
12.6;9.6 Specific Relationships Among Lattice Parameters for a High Degree of Reversibility;185
12.7;9.7 Tuning Lattice Parameters to Satisfy Two of the Proposed Conditions in the NiTiCuPd System;187
12.8;9.8 Further Comparisons with Experiment;188
12.9;9.9 Summary and Outlook: A General Method for Seeking New Classes of Functional Materials;190
12.10;References;190
13;10 Invar and Anti-Invar: Magnetovolume Effects in Fe- Based Alloys Revisited;193
13.1;10.1 Introduction;193
13.2;10.2 Invar;193
13.3;10.3 From Invar to Anti-Invar;197
13.4;10.4 Allotropy of Pure Fe;200
13.5;10.5 Ground State Properties of Invar and Anti-Invar;203
13.6;10.6 Pressure Experiments: Evidence for High Spin to Low Spin State Transitions;205
13.7;10.7 HS–LS Transitions in a Microscopic Picture;208
13.8;10.8 Questions and Outlook;211
13.9;References;212
14;11 Magnetocaloric Effect Associated with Magnetostructural Transitions;215
14.1;11.1 Introduction;215
14.2;11.2 Magnetic Cooling or Why Having a Strong Magnetocaloric Effect in a Weak Magnetic Field Makes a Difference?;215
14.3;11.3 Gd5(Si4 xGex) System and the Giant Magnetocaloric Effect;218
14.4;11.4 Altering Crystal Structures with a Magnetic Field;222
14.5;11.5 To What Extent a Structural Change Enhances the Giant Magnetocaloric Effect?;230
14.6;11.6 Conclusions;235
14.7;References;236
15;12 Entropy Change and Magnetocaloric Effect in Magnetostructural Transformations;239
15.1;12.1 Introduction;239
15.2;12.2 Multiscale Origin of the MCE in Ni–Mn–Ga Alloys;241
15.3;12.3 Direct Determination of the Entropy Change at a First- Order Transformation;245
15.4;12.4 Magnetostructural Transformation in Gd– Si– Ge Alloys;246
15.5;12.5 Conclusions;251
15.6;References;251
16;13 Functional Magneto-Structural Materials: Summary and Perspectives;253
16.1;References;259
17;Index;263