We report Na NMR studies of the polycrystalline samples of double-layer hydrated cobalt oxides NaxCoO2 · yH2O (x ∼035 and y ∼ 1.3) with the superconducting transition temperatures Tc <1.8 K and ∼4.5 K, and the dehydrated NaxCoO2 (x ∼0.35). The hyperfine field and the electric field gradient at the Na sites in the non-hydrated Na0.7CoO2 and the dehydrated Na0.35CoO2 are found to be significantly...

Recently experiments on high critical temperature superconductors have shown that the doping levels and the superconducting gap are usually not uniform properties but strongly dependent on their positions inside a given sample. We show here that the large diamagnetic signal above the critical temperature Tc and the unusual temperature dependence of the upper critical field Hc2 with the temperat...

Fully-epitaxial NbN/Co2MnSi bilayer films were grown on MgO(001) single crystalline substrates by a sputter technique. Structural, electric transport and magnetic properties were investigated for the fabricated films. The resulting NbN/Co2MnSi bilayer films show superconducting critical temperature Tc was of 16.0 K and the saturation magnetization Ms at room temperature was of 790 emu/cm3. The ...

We investigate the evolution of a superconducting string network with arbitrary, constant string current in the friction dominated regime. In the absence of an external magnetic field the network always reaches a scaling solution. However, for string current stronger than a critical value, it is different than the usual, horizon–scaling of the non-superconducting string case. In this case the f...

We find that spin polarized disordered Fermi liquids are unstable to the nucleation of superconducting pairing states at mesoscopic scales even in magnetic fields substantially higher than the critical one. We study the probability of finding superconducting pairing states at mesoscopic scales in this limit. We find that the distribution function depends only on the film conductance. The typica...

Basing on the phenomenological model of the microwave response of thin superconducting films with trapped magnetic flux elaborated in Luzhbin et al 2005 Supercond. Sci. Technol. 18 1112-7, detailed analysis of the ac linear response of a superconducting strip-line resonator cooled down in FC and ZFC regimes is presented. Special emphasis on a nonuniform distribution of the trapped vortices and ...

The properties of one-dimensional superconducting wires depend on physical processes with different characteristic lengths. To identify the process dominant in the critical regime we have studied the transport properties of very narrow (9-20 nm) MoGe wires fabricated by advanced electron-beam lithography in a wide range of lengths, 1-25  μm. We observed that the wires undergo a superconductor-i...

The response of superconducting devices to electromagnetic radiation is a core concept implemented in diverse applications, ranging from the currently used voltage standard to single photon detectors in astronomy. Suprisingly, a sufficiently high power subgap radiation may stimulate superconductivity itself. The possibility of stimulating type II superconductors, in which the radiation may inte...

Superconducting MgB2 crystallites having a size up to 3 X 2 X 1 mm have been grown using a liquidassisted-sintering process under atmospheric pressure of argon. The magnetization measurements have been carried out on MgB2 samples to determine upper critical field, critical current density and irreversibility line. The obtained values of critical current density and upper critical field were ~10...

Many heavy-fermion systems are close to a quantum critical point in that, as pressure is varied, the paramagnetic heavy-fermion phase becomes unstable to a magnetically ordered phase at zero temperature. The superconducting phases all occur within a narrow range of pressures centered around the quantum critical point. In materials such as UGe2, the paramagnetic phase is unstable to a ferromagne...