The preparation and electrical properties of high-temperature superconductor nanowire arrays are reported for the first time. YBa2Cu3O(7-delta) nanowires with widths as small as 10 nm (much smaller than the magnetic penetration depth) and lengths up to 200 microm are studied by four-point electrical measurements. All nanowires exhibit a superconducting transition above liquid nitrogen temperatu...

Thermally activated flux motion and specific electric resistance in Y358 were studied under different magnetic fields ranging from 0 to 15 kOe. Through investigating the broadening of normal-superconducting transition, we found that the thermally-activated-flux-motion model can describe the electronic effect near the superconducting transition temperature. By modifying this model, specific elec...

Inelastic light scattering studies on a single crystal of electron-doped Ca(Fe0.95Co0.05)2As2 superconductor, covering the tetragonal-to-orthorhombic structural transition as well as the magnetic transition at TSM ∼ 140 K and the superconducting transition temperature Tc ∼ 23 K, reveal evidence for superconductivity-induced phonon renormalization. In particular, the phonon mode near 260 cm−1 sh...

Condensation energy can be thought as the difference in ground state energy between the normal state and the superconducting state in a superconductor. In a way to understand and prove theory for superconducting transition, an accurate measurement of the condensation energy is needed [1]. The most common method for determination of condensation energy is by measuring the thermodynamical critica...

Within the kinetic energy driven superconducting mechanism, the effect of the pressure on superconductivity in the doped two-leg ladder cuprates is studied. It is shown that the superconducting transition temperature in the doped two-leg ladder cuprate superconductors increases with increasing pressure in the underpressure regime, and reaches a maximum in the optimal pressure, then decreases in...

The relationship between the cuprate pseudogap (Δ(p)) and superconducting gap (Δ(s)) remains an unsolved mystery. Here, we present a temperature- and doping-dependent tunneling study of submicron Bi(2)Sr(2)CaCu(2)O(8+δ) intrinsic Josephson junctions, which provides a clear evidence that Δ(s) closes at a temperature T(c) (0) well above the superconducting transition temperature T(c) but far belo...

We have studied the reversible pressure induced structural transition (primitive cubic to polymeric monoclinic) of Na2CsCGoand the superconductivity in both phases. We have established that the polymeric phase of Na2CsC60 is superconducting with an ambient pressure transition temperature about 3 K lower than that for the primitive cubic phase. We believe that an analogous lowering of the transi...

We have studied niobium superconducting thin wires deposited onto a SrTiO3 substrate. By measuring the reflection coefficient of the wires, resonances are observed in the superconducting state in the 130 MHz to 4 GHz range. They are interpreted as standing wave resonances of one-dimensional plasma modes propagating along the superconducting wire. The experimental dispersion law, omega versus q,...

In the quest for a microscopic theory for the superconductivity in cuprates, one hotly debated issue is the temperature at which Cooper pairs first form. Do pairs form at the critical temperature Tc or do they form at higher temperatures lacking phase rigidity? To answer the question, we have developed new techniques, based on scanning tunneling microscopy, to visualize the process of the pair ...