Why is there no bulk specific heat anomaly at the superconducting transition temperature of BaPb(1-x) Bi(x) O(3)?

Caloric measurements have shown that there is no bulk specific heat anomaly at the superconducting transition temperature of BaPb(0.75)Bi(0.25)O(3).

Ternary transition metal phosphides: High-temperature superconductors.

Two systems of ternary transition metal phosphides with the ordered Fe(2)P-type hexagonal structure are reported. They have the general formula MRuP and MOsP, in which M can be Ti, Zr, or Hf. An onset of the superconducting transition temperature as high as 13.0 K is reported for the ZrRuP compound.

High-field, high-current superconductors.

This article deals with superconducting materials which have zero electrical resistance while carrying high electrical current densities (around 10(6) amperes per square centimeter) in high magnetic fields (up to 50 teslas). The technological importance of these materials is due to their use in the windings of loss-free electromagnets which generate high magnetic fields. Such magnets are the foundation for superconducting electrotechnology, a rapidly growing field whose applications include advanced electrical machines and fusion reactors. The article focuses primarily on the materials aspects of this new techology. A brief overview is given of the physical principles which underlie this special type of superconducting behavior, and some of the important basic parameters are examined. The technology required to adapt the materials to electromagnets is also discussed. A few concluding remarks concern future possibilities for materials that can be used in generating very high magnetic fields.

Enhancement of Superconductivity through Lattice Softening.

The superconducting transition temperature of an iridium-yttrium eutectic is enhanced extraordinarily through lattice softening. This is shown by a drastically reduced Debye temperature.

P-State Pairing and the Ferromagnetism of ZrZn2.

It is ascertained that, within the range of stability, the transition temperature of the superconducting solutions between Ti and Zr and between Zr and Hf, and the Curie point of the corresponding ferromagnetic solutions between TiZn(2) and ZrZn(2) and between ZrZn(2) and HfZn(2), follow a parallel behavior. From this correlation it is concluded that the weak itinerant ferromagnetism of ZrZn(2) must be due to electron-phonon interaction. Theoretical arguments are advanced to show that the underlying mechanism is hindered p-state pairing, due to a strongly localized repulsive part of the pair-potential that acts as a Hubbard interaction and gives rise to a Stoner instability.

Clustering hypothesis of some high-temperature superconductors.

Cluster formation in metallic crystal lattices is important for most high-temperature superconductors.

High superconducting transition temperatures of new rare earth ternary borides.

A new group of ternary borides has been found that show either ferromagnetism or superconductivity. Their general formula is MRh(4)B(4) where M is a transition or rare-earth element. Their superconducting transition temperatures range from approximately 2.5 K for the Sm compound to approximately 12 K for the Lu compound.

Crystallography of new ternary borides.

The structure of new ternary rhodium borides has been determined. Isomorphism with the corresponding ternary cobalt borides is established.

Rare-earth oxides of manganese and cobalt rival platinum for the treatment of carbon monoxide in auto exhaust.

The perovskite-like compounds RE(1-X)Pb(5)MnO(3) and RECoO(3), where RE (rare earth) is lanthanum, praseodymium, or neodymium, are active catalysts for the oxidation of carbon monoxide. Crushed single crystals of these compounds compare favorably with commercial platinum catalysts in initial activity and lifetime. Therefore, these compounds are promising substitutes for platinum in devices for the catalytic treatment of auto exhaust.

High-temperature superconductors, the first ternary system.

A new system of high-temperature superconductors is reported. The compounds, Mo(6 - x)A(x)S(6) where A is Cu, Zn, Mg, Ag, Cd, Sn, or Pb, are rhombohedral with a approximately 6.5 angstroms and approximately 90 degrees . The transition temperatures range from approximately 2.5 degrees K for the Cd compound to approximately 13 degrees K for the Pb compound.

Superconductivity of Double Chalcogenides: Lix Ti1.1S2.

Lithium titanium sulfides, Li(x)Ti(1.1)S(2)(0.1 x

Instabilities of high temperature superconductors.

We have observed the transition temperature of both the cubic and tetragonal phases of several high-temperature beta-W superconductors. The instability of the cubic lattice appears to be characteristic of high-temperature superconductors.

Superconductivity: the transition temperature peak below four electrons per atom.

It is shown that the superconducting transition temperature for compounds in seven different structure types exhibits a peak at about 3.7 to 3.9 valence electrons per atom.

Rare Earth impurities in yb(6) and zrb(12).

We present data on the depression of the superconducting transition temperatures of YB(6) and ZrB(12) by rare earth impurities. These data show unusual features. Ce in YB(6) is in some ways analogous to Yb in ZrB(12), and this analogy also appears to hold between Ce in CeB(6) and YB in YbB(12).

Ferromagnetism and superconductivity in uranium compounds.

The intimate correlation between the mechanisms causing magnetism and superconductivity in uranium compounds has been verified again-in novel systems.

Rare-Earth elements and high pressures.

Praseodymium, under very high pressures, shows a magnetic behavior similar to that of cerium at normal pressure.

Magnetic ordering in the rare-Earth hexaborides.

Magnetic ordering in the rare-earth hexaborides has been studied by a variety of methods, and a clear correlation with the presence of conduction electrons has been found.

Superconducting phosphorus.

Phosphorus, the element itself, becomes superconducting near 4.7 degrees K and at pressures exceeding 100 kilobars. This constitutes one of the four last missing links in the proof that superconductivity is normal behavior for every truly metallic sp element. The three remaining ones are arsenic, sulfur, and iodine.

Superconductivity and antiferromagnetism in boron-rich lattices.

Ferromagnetism, antiferromagnetism, or superconductivity has been discovered in most hexa- and dodecaborides.