Four regimes of vortex motion were identified in the magnetoresistance of Bi2Sr2CaCu2O8+δ single crystals: (1) thermally activated flux flow (TAFF) in samples with surface defects caused by thermal annealing; (2) TAFF-like plastic motion of highly entangled vortex liquid at low temperatures, with Upl ∼ (1− T/Tc)/H ; (3) pure free flux flow above the region of (2) in clean and optimally doped sa...

The magnetoconductivity in Fe doped YBa 2 Cu 3 O 7-δ single crystals has been measured in the temperature region above T c where superconducting fluctuations are known to be important. For small Fe concentrations and B//c we obtain excellent agreement with accepted fluctuation theories. However, at higher Fe concentrations this description seems to break down. For B⊥c we observe an anomalous de...

We present an approach that allows the reconstruction of the zero-field magnetic penetration depth λ0 based on the results of muon-spin-rotation (μSR) experiments conducted in a superconductor in the vortex state. It was successfully applied to describe the μSR experiments in optimally doped (BiPb)2(SrLa)2CuO6+δ (OP Bi2201). We found that in unconventional d-wave superconductors (such as OP Bi2...

For an electron gas with a δ-function attraction we investigate the crossover from weak-coupling to strong-coupling superconductivity near zero temperature as well as near the temperature T , at which the strong coupling produces a pseudogap in the energy spectrum due to the binding of electron pairs. We present curves for the behavior of the superconductive transition temperature, the gap form...

Tunnel junctions (TJs) are essential for high-performance multijunction solar cells to act as transparent low resistance paths carriers travel between adjacent cells. However, TJs typically exhibit highly degraded tunneling performance due unwanted dopant out-diffusion during top cell growth. In this study, GaAs with Si and Te delta-doping (δ-doping) were grown via solid source molecular beam e...

We report on three different and complementary measurements, namely magnetisation measurements positron annihilation spectroscopy and NMR measurements, which give evidence that the formation of oxygen vacancy clusters is on the origin of the fishtail anomaly in YBa2Cu3O7−δ. While in the case of YBa2Cu3O7.0 the anomaly is intrinsically absent, it can be suppressed in the optimally doped state wh...

Novel biomaterials based on hydrophilic polycaprolactone and polyurethane (Tecophilic®) nanofibers with an encapsulated 5,10,5,20-tetraphenylporphyrin photosensitizer were prepared by electrospinning. The doped nanofiber textiles efficiently photo-generate O(2)((1)Δ(g)), which oxidize external chemical and biological substrates/targets. Strong photo-virucidal effects toward non-enveloped polyom...

Abstract Composite thermoelectric materials based on layered calcium cobaltite Ca 3 Co 4 O 9 + δ doped with copper particles were synthesized by two-step sintering, and their microstructure, electrotransport properties studied. It was determined that the introduction of into ceramics improves sinterability at moderate sintering temperatures ( T sint ≤ 1273 K), leading to a decrease in porosity ...

Lately, ceramic fuel cells (CFCs) have held exceptional promise for joint small- and large-scale applications. However, the low-oxygen reduction response of cathode materials has hindered low operating temperature CFCs. Herein, we developed a semiconductor based on La Ce co-doped SrCoO3 embedded them in porous Ni-foam to study their electrochemical properties. The Ni-foam-pasted La0.2Sr0.8Co0.8...

We have performed angle-resolved photoemission and core-level x-ray photoemission studies of the single-layer cuprate Bi2Sr2−xLaxCuO6+δ (Bi2201) and revealed the doping evolution of the electronic structure from the lightly-doped to optimally-doped regions. We have observed the formation of the dispersive quasi-particle band, evolution of the Fermi “arc” into the Fermi surface and the shift of ...