Carbon Based Magnetism

Editors’ Preface

Foreword

Chapter 1: Localized Spins Exchange-coupled with Itinerant Electrons in Organic π-electronic System

1 Preface

2 High Spin Hydrocarbons as a Model for One-dimensional Organic Ferromagnet

3 Spin Alignment Based on Itinerant Electron

4 Spin Alignment via Charge Transfer Interaction

5 Design of Spin-polarized Donors

6 Molecular and Crystal Design for Organic Ferromagnetic Metal

7 Conducting and Magnetic Properties of Networked Gold Nanoparticles Connected by Spin-polarized Molecular Wires

8 Summary

Chapter 2: Magneto-structural Correlations in π-Conjugated Nitroxide-based Radicals: Hydrogen-bonds and Related Interactions in Molecular Organic Solids

1 Introduction

2 Exchange and Crystal Assembly in Phenolic Nitronynitroxides

3 Bio-inspired Molecular Recognition for Crystal Assembly

4 Exchange and Crystal Assembly in Nitronylnitroxides with Hydrogen-bonding Azaarenes

5 Exchange and Crystal Assembly in Tert-butylnitroxides with Hydrogen-bonding Azaarenes

6 Exchange and Crystal Assembly in Cyclic Aza-Radicals Bearing Carboxylic Acid Groups

7 Exchange and Crystal Assembly in Aryl Tert-butylnitroxides Bearing Carboxylic Acid Groups

8 Conclusion

Acknowledgements

Chapter 3: Persistent High-spin Organic Polyradicals

1 Introduction

2 Spin Alignment of Non-Kekulé and Non-Disjoint Molecules

3 π-conjugated Polymers Bearing Aminium Cationic Radicals for High-spin Alignment at Room Temperature

4 m-phenylene-connected and Cross-conjugated Arylaminium Cationic Radicals

5 Two-Dimensionally Extended Poly(aminium cationic radical)s

Chapter 4: Verdazyl-based Magnetic Systems

1 Introduction

2 General Magnetic Properties of Verdazyl Radical Crystals

3 Ferromagnetism in Verdazyl Radical Crystals

4 Antiferromagnetism in Verdazyl Radical Crystal

5 Weak Ferromagnetism in Verdazyl Radical Crystals

6 Spin Peierls Transition in Verdazyl Radical Crystals

7 Spin Frustration in Verdazyl Radical Crystals

8 Magnetic Property of Verdazyl Radical Alloy

9 Photo-Excited High Spin States on π-Conjugated Verdazyl Radicals

10 Transition Metal Complex of Verdazyl Radicals

11 Magnetic Conductors Based on Verdazyl Radicals

Chapter 5: Quantum Spin Magnetism in Nitroxide-based Compounds

1 Introduction

2 A Zigzag Spin Chain, F2PIMNH [14]

3 Polyradical Approach

4 Spin Ladder

5 Ferrimagnetism

6 Spin Frustration

7 Pressure Effects

8 Field Induced Magnetic Ordering

Acknowledgements

Chapter 6: The Magnetism of π-Orbitals under Pressure

1 Introduction

2 Experiments under Pressure

3 Pressure Effects on Genuine Organic Antiferromagnets

4 Pressure Effects on Genuine Organic Ferromagnets

5 Pressure Effects on Sulfur-based Organic Magnets with Ferromagnetic Moments

6 Other Interesting Pressure Effects on Thermally and Structurally Unstable Compounds

7 Conclusion

Chapter 7: Spin Density Distribution and Interaction Mechanisms in Thiazyl-based Magnets

1 Introduction

2 Spin Densities in the Dithiadiazolyl Ring

3 Spin Density Studies on thep-nitro-tetrafluorophenyl- dithiadiazolyl radical (3)

4 Magnetic Interactions in Dithiadiazolyl Radicals

5 Other Thiazyl Radicals

6 Conclusions

Chapter 8: Magnetic Bistability in Molecule-based Magnetic Materials

1 Introduction

2 Magnetic Bistability in Organic Radical Solids

3 Molecule-based Magnetic Bistable Materials

4 Summary

Chapter 9: The Nature of Effective Exchange Interactions

1 Introduction

2 The Nature of Chemical Bonds and Magnetic Interactions

3 Less Screening Rule and Hund Rule

4 Spin Polarization Rule and Related Spin Alignment Rules

5 Intermolecular Spin Alignment Rules

6 Conclusion

Chapter 10: Magnetism of Fullerene Charge-transfer Complexes

1 Introduction

2 TDAE-C60

3 Higher Fullerenes Reduced with TDAE

4 Reduction of C60 with Different Organic or Organometallic Donors

5 Charge Transfer Complexes of C60 Derivatives

6 Intercalation of Magnetic Ions

Chapter 11: Diamagnetism of Diamond and Graphite

1 Introduction

2 Theory of (Dia)magnetism

3 Diamagnetism of Diamond

4 Graphite: Electronic Band Structure

5 Graphite: Magnetic Susceptibility

7 Concluding Remarks

Acknowledgements

Chapter 12: Electronic and Magnetic Properties of Nanographites

1 Introduction

2 Electronic States of Nanographite Ribbons

3 Electronic States in a Magnetic Field

4 Bearded Edge and Cove Edge

5 Connection with Anisotropic Superconductivity

6 Orbital Diamagnetism and Pauli Paramagnetism

7 Magnetic Instability

8 Summary

Chapter 13: Flat-band Ferromagnetism in Organic Crystals

1 Introduction

2 Effective Models for Nano-graphite

3 Nano-graphite and Edge States

4 Flat-band Ferromagnetism in Organic Materials

5 Materials Design of Magnetic Carbon

6 Summary and Discussion

Chapter 14: Magnetism in Nanometer-scale Materials that Contain No Magnetic Elements

1 Preamble

2 Density Functional Theory

3 Edge States of Zigzag-shaped Graphite Ribbons

4 Magnetic Ordering Related to Border States

5 Magnetic Carbon Nanotubes

6 Magnetism on Si Surfaces

7 Concluding Remarks: Quantum Design of Nanomagnets

Acknowledgements

Chapter 15: Interactions and Disorder in 2D Graphite Sheets

1 Introduction

2 The Elecronic Structure of Graphene Sheets

3 The Long Range Coulomb Interactions in Graphite

4 Effects of Disorder

5 Combined Effects of Disorder and the Electronic Interactions

6 Coupling between Graphene Layers

7 Conclusions

Chapter 16: The Magnetic Nature of Intrinsic and Irradiation-induced Defects in Carbon Systems

1 Introduction

2 Methodology

3 Magnetic Properties of the Frenkel Pair in Carbon Systems

4 Magnetism Stimulated by Non-magnetic Impurities

5 Conclusions and Outlook

Chapter 17: Unconventional Magnetic Properties of Nanographite

1 Introduction

2 What Theory Predicts on the Electronic and Magnetic Structure of Nanographene

3 Electronic and Magnetic Features of Nanographite and Networked Nanographites

4 Nanographite Grown in sp2/sp3 Mixed Nano-carbon

5 Host-guest Interaction and Edge-state Spins

6 Summary

Acknowledgements

Chapter 18: Ferromagnetic and Superconducting Instabilities in Graphite

1 Introduction

2 Ferromagnetism in Carbon Materials: a Comparative Study

3 Oxygen adsorption Effect on the Magnetic Properties of Graphite

4 Coexistence of Superconducting and Ferromagnetic Instabilities in Graphite-sulfur Composites

5 Discussion and Concluding Remarks

Chapter 19: Induced Magnetic Order by Ion Irradiation of Carbon-based Structures

1 Motivation

2 Irradiation Characteristics

3 Irradiation Effects

4 Annealing and Aging Effects

5 Conclusion and Open Issues

Acknowledgements

Chapter 20: Magnetic Properties of Novel Carbon Allotropes

1 Introduction

2 Strongly Paramagnetic and Ferromagnetic Pure Carbons

3 Causes of Para- and Ferromagnetism in Pure Carbon

4 Synthesis Techniques

5 Concluding Remarks

Chapter 21: McConnel Model for the Magnetism of C60-based Polymers

1 Introduction

2 C60-Polymers: A brief overview

3 Carbon Magnetism: A Member of a New Magnetic Class?

4 Defects in Carbon-based Materials

5 Theoretical Models

6 Magnetic C60 Polymers Revisited

7 Discussion and Conclusions

Acknowledgments

Chapter 22: The Mechanism of the Magnetic Interaction in Polymeric-C60 Fullerenes

1 Introduction

2 Methodological Considerations

3 The Cage-vacancy Mechanism

4 The Open-cage Mechanism

5 The Interfragment Bond-breaking Mechanism

6 Summary and Conclusions

Acknowledgments

Chapter 23: Ferromagnetism in Defective Polymerised C60

1 Introduction

2 Methodology

3 Pristine Rh-C60

4 Prototype Defective Structures: Vacancy Defects

5 Spontaneous Formation of Defects from Pressure

6 Spontaneous Formation of Defects from Pressure and Temperature

7 A Ferromagnetic Ground State in the presence of Hydrogen

8 Conclusions

Acknowledgements

Chapter 24: Ferromagnetic Carbonaceous Compounds

1 Introduction

2 Experimental Evidence

3 Summary of Experimental Observations

4 Theoretical Models

5 Conclusions

Subject Index