Crystallography of the high critical temperature oxide superconductors

Normal state of the copper oxide high-temperature superconductors.

Breakdown of one-parameter scaling in quantum critical scenarios for high-temperature copper-oxide superconductors.

We show that if the excitations which become gapless at a quantum critical point also carry the electrical current, then a resistivity linear in temperature, as is observed in the copper-oxide high-temperature superconductors, obtains only if the dynamical exponent z satisfies the unphysical constraint, z < 0. At fault here is the universal scaling hypothesis that, at a continuous phase transit...

Electronic phase diagram of high-temperature copper oxide superconductors.

In order to understand the origin of high-temperature superconductivity in copper oxides, we must understand the normal state from which it emerges. Here, we examine the evolution of the normal state electronic excitations with temperature and carrier concentration in Bi(2)Sr(2)CaCu(2)O(8+δ) using angle-resolved photoemission. In contrast to conventional superconductors, where there is a single...

Kiloampere, Variable-Temperature, Critical-Current Measurements of High-Field Superconductors

We review variable-temperature, transport critical-current (I c) measurements made on commercial superconductors over a range of critical currents from less than 0.1 A to about 1 kA. We have developed and used a number of systems to make these measurements over the last 15 years. Two exemplary variable-temperature systems with coil sample geometries will be described: a probe that is only varia...

Pairing Symmetry of the High Temperature Superconductors

A review of relevant experiments that favour an unconventional pairing symmetry in high temperature cuprates is made. Results of magnitude sensitive techniques are discussed and then tests which probe directly the phase of the order parameter are presented in more detail. Josephson eeect and its relevance to this problem is described. Consensus resulting from compelling arguments for a d x 2 ?y...