High-Pressure and Low-Temperature Physics

High pressure science is a rapidly growing diverse fi. e1d. The high pressure technique has become a powerful tool for both the study and preparation of materials. In spi. te of the many high pressure conferences held in recent years, I felt that there was a need for scientists within a well-defined area (not bound merely by the common experimental technique) to meet in an atmosphere conducive to frank exchange and close interaction. In this spirit, the Cleveland State University hosted such a conference from July 20 to 22, 1977, in which the physics of solids under high pressures and at low tempera­ tures was specifically examined. Both the original and review papers presented at the conference and the candid discussions following their presentations appear in this volume. They clearly cover a rather complete spectrum of current research in the physics of solids at high pressures and low temperatures. I wish to thank the National Aeronautics and Space Administra­ tion, the Office of Naval Research and the National Science Founda­ tion for their financial support of the conference. In addition, I wish especially to thank Steinar Huang for his unceasing assistance in arranging this conference. I also wish to thank him and Francis Stephenson for their assistance in preparing this book. C. W. Chu, Chairman, International Conference on High Pressure and Low Temperature Physics v Contents HYDROGEN AND METAL-HYDRIDES (Chairman: I. Spain) PROSPECTS FOR METALLIC HYDROGEN 1 A. L.

Table of Contents:
Hydrogen and Metal-Hydrides.- Prospects for Metallic Hydrogen.- Metallic Hydrogen: Recent Theoretical Progress.- High Hydrogen Pressures in Superconductivity.- Fermi Surface and Magnetism.- The Role of Pressure in the Study of the Fermi Surface.- Electronic Structures of Ferromagnetic 3d-Transition Metals at Normal and High Pressures.- Neutron Scattering at High Pressure in Singlet-Triplet Systems.- Some Magnetization Studies at High Hydrostatic Pressures.- Pressure-Induced Electronic Transition in CeAl2.- Valence Instabilities.- Valence Instabilities of Rare Earth Ions in Metals.- Theoretical Approach to the Configuration Fluctuation in Sm-Chalcogenides.- The ?-? Phase Transitions in Ce-Th Alloys under High Pressure.- The Pressure Dependence of the Magnetic Susceptibility of Rare Earth Substituted Samarium Sulfide.- Pressure Dependence of Crystal Field Parameters in Rare Earth Intermetallic Compounds.- Pressure Induced Spin-Glass?Single-Impurity Transition in LaCe, Superconductivity in LaCe and YCe under Pressure.- Tricritical Behavior and Soft Mode Transitions.- Stress Effects on Critical Behaviour.- Tricritical Point in KDP.- Investigation of the Tricritical Point of KDP under Pressure.- High Pressure Studies of Soft Mode Transitions in Solids.- Pressure Dependence of Raman Scattering in Ferroelectrics and Ferroelastics.- Brillouin Scattering at High Pressures.- Superconductivity and Structural Instabilities.- Anharmonicity in A15 Superconductors: A Thermal Expansion Approach.- High Pressure Structural and Lattice Dynamical Investigations at Reduced Temperatures.- High Temperature Superconductivity and Instabilities.- The Isothermal Pressure Derivatives of the Elastic Shear Modulus for V3Si.- LaAg under Hydrostatic Pressure: Superconductivity and PhaseTransformation.- Superconductivity.- Pressure Dependencies of the Superconducting and Magnetic Critical Temperatures of Ternary Rhodium Borides.- The AuGa2 Dilemma — Superconducting Version.- Superconductivity of BCC Barium under Pressure.- Superconducting Behaviour of Nb3Ge thin Films under Hydrostatic Pressure.- Pressure Dependence of Tc in the Superconducting A15 Compounds V75-xTMxGa25 (TM = Cr, Mn, Fe, and Co).- Superconductors and Semiconductors.- New Hypothesis Concerning the Commencement of the Rare Earth Series at High Pressure.- Pressure-Induced Covalent-Metallic Transitions.- New Hydrostatic Pressure Results on Sulfur Impurity Center in GaSb.- Low Temperature Light Induced Change of the Chlorine Center Configuration in CdTe.- Techniques.- Narrow Gap Semiconductors as Low Temperature Pressure Gauges.- Bi Phase Transitions below 80K to 150 Kbar in an Ar Pressure Medium.- Piston-Cylinder Apparatus Operating at Liquid Helium Temperature.- He3 Cryostat with High Pressure Hydrogen Chamber for Superconductivity Measurements in Metal-Hydrogen Alloys.- Effects of Pressure, Temperature and Defect Concentration on Positron Behavior in Metals.- Low Dimension Conductors.- Dimensionality Effects and Physical Properties in 1D Compounds.- Neutron Diffraction Study of the Compressibility of TTF-TCNQ and KCP under Hydrostatic Pressures up to about 20 Kbar.- The Role of Librations in TTF-TCNQ.- The Commensurate-Incommensurate Phase Transition.- Conference Review.- The Conference: One Man’s View.- Conference Attendees.