Superconductivity in Ternary Compounds II: Superconductivity and Magnetism

ISBN-13: 9783642818967 / Angielski / Miękka / 2011 / 308 str.

M. B. Maple; O. Fischer

Opis

This Topics in Current Physics (TCP) Volume 34 is concerned primarily with super- conductivity and magnetism, and the mutual interaction of these two phenomena in ternary rare earth compounds. It is the companion of TCP Volume 32 - Superconduc- tivity in Ternary Compounds: Structural, Electronic and Lattice Properties. The interplay between superconductivity and magnetism has intrigued theoreticians and experimentalists alike for more than two decades. V. L. Ginzburg first addressed the question of whether or not superconductivity and ferromagnetism could coexist in 1957, and B. T. Matthias and coworkers carried out the first experimental inves- tigations on this problem in 1959. The early experiments were made on systems that consisted of a superconducting element or compound into which small concentrations of rare earth impurities with partially-filled 4f electron shells had been intro- duced. These dilute impurity systems were chosen because the scattering of conduc- tion electrons by parama9. netic rare earth impurity ions usually has a strong de- structive "pa i r breaking" effect on superconducti vity, typi ca lly drivi ng the super- conducting transition temperature to zero at impurity concentrations of only a few atomic percent. Unfortunately, analysis of these early experiments was complicated by clustering and/or the formation of short range or "glassy" types of magnetic order so that definitive conclusions regarding the coexistence of superconductivity and magnetism could not be reached.

Spis treści

1. Magnetic Superconductors.- 1. 1 Introduction.- 1. 2 How The Problem of Magnetic Superconductors Originated.- 1. 3 Pairbreaking Effects — Impurities and External Fields.- 1. 4 Impact of Ternary Rare Earth Compounds.- 1. 5 Antiferromagnetic Superconductors.- 1. 6 Ferromagnetism and Superconductivity.- 1. 7 Superconductivity and Competing Magnetic Interactions.- 1. 8 Concluding Remarks.- References.- 2. Systematics of Superconductivity in Ternary Compounds.- 2. 1 Review of Superconductivity in Ternary Compounds by Structure Class.- 2. 1. 1 Compounds with MT4B4 Stoichiometry.- a) Primitive Tetragonal CeCo4B4 Structure.- b) Body-Centered-Tetragonal LuRu4B4 Structure.- c) Orthorhombic LuRh4B4 Structure.- d) Other MT4B4 Structure Types.- 2. 1. 2 Orthorhombic LuRuB2 Structure.- 2. 1. 3 CeCo3B2 and Related Structures.- a) Hexagonal CeCo3B2 Structure.- b) Monoclinic ErIr3B2 Structure.- c) Hexagonal Ba2/3Pt3B2 and LaRu3Si2 Structures.- d) Other MT3B2 Variants.- e) Hexagonal ZrRuSi Structure.- 2. 1. 4 Primitive Cubic Pr3Rh4Sn13 and Related Structures.- a) Pr3Rh4Sn13 Structure.- b) Ternary Compounds Related to Pr3Rh4Sn13-Type Materials.- 2. 1. 5 Primitive Tetragonal Sc2Fe3Si5 Structure.- 2. 1. 6 Primitive Tetragonal Sc5Co4Si10 Structure.- 2. 2 Concluding Remarks.- 2A. Appendix: Tables of Crystallographic, Superconducting and Magnetic Data for 14 Classes of Ternary Compounds.- References.- 3. Critical Fields of Ternary Molybdenum Chalcogenides.- 3. 1 Overview of Experimental Results.- 3. 2 Summary of Theory.- 3. 2. 1 Ginzburg-Landau Theory.- 3. 2. 2 Microscopic Theory.- a) Isotropic, Weak Coupling Superconductors.- b) Strong-Coupling and Exchange Effects.- c) Anisotropy and Multiband Effects.- 3. 3 The Role of Impurities.- 3. 3. 1 Mo6Se8.- 3. 3. 2 PbMo6S8.- 3. 4 Anisotropy.- 3. 4. 1 MxMo6X8 Compounds.- 3. 4. 2 T?2Mo6Se6.- 3. 5 The Temperature Dependence of Hc2 and the Question of the Paramagnetic Limitation.- 3. 6 Compounds with Magnetic Ions. The Jaccarino-Peter Effect.- 3. 7 Critical Currents and the Problem of Wire Production.- References.- 4. Superconductivity, Magnetism and Their Mutual Interaction in Ternary Rare Earth Rhodium Borides and Some Ternary Rare Earth Transition Metal Stannides.- 4. 1 Background.- 4. 2 Ternary RERh4B4 Compounds.- 4. 2. 1 Nonmagnetic Superconducting RERh4B4 Compounds: RE = Lu, Y.- 4. 2. 2 Rate of Depression of Tc in (Lu1?xREx)Rh4B4.- 4. 2. 3 Ferromagnetic Nonsuperconducting RERh4B4 Compounds: RE = Gd, Tb, Dy, Ho.- 4. 2. 4 Ferromagnetic Superconducting RERh4B4 Compounds: RE = Er.- 4. 2. 5 Antiferromagnetic Superconducting RERh4B4 Compounds: RE = Nd, Sm, Tm.- 4. 3 Pseudoternary RERh4B4 Compounds.- 4. 3. 1 (RE1?xREx’)Rh4B4 Compounds.- 4. 3. 2 RE(MxRh1?x)4B4 Compounds.- 4. 4 Ternary REMxSny Compounds.- 4. 5 Summary.- References.- 5. Superconductivity and Magnetism in (RE)Mo6X8 Type Compounds.- 5. 1 Ternaries.- 5. 1. 1 Re-Entrant Superconductors.- 5. 1. 2 Antiferromagnetic Superconductors.- 5. 1. 3 Other Ternaries with Ce, Eu, Tm and Yb.- 5. 2 Pseudoternaries.- 5. 3 Analysis of Upper Critical Field Curves.- 5. 4 Overview of Exchange Interactions in (RE)Mo6X8 Compounds.- 5. 5 Summary.- References.- 6. Electronic Structure and Superconductivity/Magnetism in Ternary Compounds.- 6. 1 Theoretical Approach.- 6. 1. 1 Local Density and Local Spin-Density Formalism.- 6. 1. 2 Linearized Muffin-Tin Orbital Method.- 6. 2 Chevrel Phase Compounds.- 6. 2. 1 Energy Band Calculations.- 6. 2. 2 Results for the Paramagnetic States.- a) Band Structure, Density of States and Resulting Properties.- b) Intra-Cluster Versus Inter-Cluster Effects and Superconductivity.- c) Charge Transfer and Magnetic Isolation.- d) Magnetic Response of Conduction Electrons: Stoner Factor.- e) Superconductivity: Calculation of Electron-Phonon Coupling Parameter ?.- 6. 2. 3 Results for Ferromagnetic Structures.- a) Spin-Polarized Band Structure and Magnetization.- b) Increase of Hc2 with Doping of Magnetic Impurities: Jaccarino-Peter Mechanism.- c) Hyperfine Fields.- 6. 3 Ternary Rhodium Borides.- 6. 3. 1 Energy Band Calculations.- 6. 3. 2 Energy Band Results.- 6. 3. 3 Magnetic Ordering.- 6. 3. 4 Superconductivity.- 6. 3. 5 Effect of Local Moments on Tc.- 6. 3. 6 Re-Entrant Magnetism in ErRh4B4.- 6. 3. 7 Mixed State of Magnetism and Superconductivity in ErRh4B4.- References.- 7 NMR and Mössbauer Studies in Ternary Superconductors.- 7. 1 Mössbauer Effect Studies of Local Vibrational Modes.- 7. 2 Conduction Electron-Local Moment Interactions in Paramagnetic Ternary Compounds.- 7. 2. 1 Chevrel Phases.- 7. 2. 2 Rhodium Borides.- 7. 3 Local Moments in Magnetically Ordered Rare-Earth Compounds.- 7. 3. 1 Hyperfine Fields and Magnetic Moments.- 7. 3. 2 Rare-Earth Rhodium Borides.- 7. 3. 3 Ternary Silicides.- 7. 3. 4 Ternary Stannides and Chevrel Phase Compounds.- 7. 4 Crystal Chemistry and Charge Transfer.- 7. 5 Conclusions.- References.- 8. Neutron Scattering Studies of Magnetic Ordering in Ternary Superconductors.- 8. 1 Neutron Scattering Theory.- 8. 1. 1 Coherent Bragg Diffraction.- 8. 1. 2 Phase Transitions and Critical Scattering.- 8. 2 Antiferromagnetic Superconductors.- 8. 2. 1 Magnetic Structures.- 8. 2. 2 Magnetic Moment and Spin Direction.- 8. 2. 3 Magnetic Field Dependence.- 8. 3 Ferromagnetic Superconductors.- 8. 3. 1 Ferromagnetic State.- 8. 3. 2 Oscillatory Behavior.- References.- 9. Theory of Magnetic Superconductors.- 9. 1 Influence of Spin Scattering on Superconductivity.- 9. 1. 1 Electron-Spin Susceptibility.- a) No Spin-Orbit and Exchange Scattering.- b) Finite Spin-Orbit and Exchange Scattering.- 9. 1. 2 Paramagnetic Phase.- a) Static Approximation.- b) Dynamic Correlations.- 9. 1. 3 Magnetically-Ordered Systems.- a) Uniform Exchange Field.- b) Antiferromagnetic Order.- 9. 2 Magnetic Structures in Superconductors Resulting From Exchange Interactions.- 9. 2. 1 Anderson-Suhl Cryptoferromagnetism.- 9. 2. 2 Ginzburg-Landau Regime.- 9. 2. 3 Phase Diagram for Cryptoferromagnetic Spin Structures.- 9. 3 The Magnetic State in the Presence of Electromagnetic Coupling.- 9. 3. 1 Ginzburg-Landau Functional.- 9. 3. 2 Survey of Solutions of the Ginzburg-Landau Equations.- 9. 3. 3 Inhomogeneous Phases.- a) Blount-Varma Theory.- b) Vortex States.- c) Influence of Fluctuations.- 9. 4 Alternative Forms of Pairing States.- 9. 4. 1 Ground States with Finite Pairing Momentum.- 9. 4. 2 P-Wave Pairing.- References.- Additional References with Titles.