Related papers: Self-Organized Criticality Effect on Stability: Ma…
A systematic study of the weak- link behavior for YBa2Cu3O7-d polycrystalline samples has been done using the electrical resistivity and AC susceptibility techniques.The experiments were performed with two samples of similar grain, a sample…
Magneto-optical imaging and magnetization measurements were applied to investigate local formation of superconducting phase effected by a random neck synthesis in Y-Ba-Cu-O system. Polished pellets of strongly inhomogeneous ceramic samples…
The penetration of magnetic flux into a thin film of YBa$_2$Cu$_3$O$_{7-x}$ is studied when the external field is ramped slowly. In this case the flux penetrates in bursts or avalanches. The size of these avalanches is distributed according…
We combine the BCS self-consistency condition, a semiclassical expansion for the spectral density and interaction matrix elements to describe analytically how the superconducting gap depends on the size and shape of a 2d and 3d…
The magneto-conductance in YBCO grain boundary Josephson junctions, displays fluctuations at low temperatures of mesoscopic origin. The morphology of the junction suggests that transport occurs in narrow channels across the grain boundary…
The magnetization M of a thin YBaCuO film is measured as a function of the angle $\theta $ between the applied field H and the c-axis. For fields above the first critical field, but below the Bean's field for first penetration H*, M is…
The dependence of the magnetic field strength required for levitation of a melt textured, single domain YBCO superconductor disc on the frequency of the current generating the levitating magnetic field has been investigated. The magnetic…
Fundamental and higher harmonics of the AC magnetic susceptibility have been measured on a LaO_0.92F_0.08FeAs sample as a function of the temperature, at various amplitudes and frequencies of the AC magnetic field, with a small superimposed…
We study the effect of a single bistable scatterer on conductance of mesoscopic conductors in the crossover regime from open to closed systems. After the resistance of the contact between the metallic grain and bulk electrode exceeds the…
Self-organized criticality is a well-established phenomenon, where a system dynamically tunes its structure to operate on the verge of a phase transition. Here, we show that the dynamics inside the self-organized critical state are…
As an example for a seemingly simple but actually intricate problem, the Bean critical state is studied in a superconducting strip of finite thickness d and width 2w >> d placed in an oblique magnetic field. The analytical solution is…
Magneto-fluctuations of the normal resistance R_N have been reproducibly observed in high critical temp erature superconductor (HTS) grain boundary junctions, at low temperatures. We attribute them to mesoscopic transport in narrow channels…
We show that in Pr$ _{0.5} $La$ _{0.2} $Ca$ _{0.3} $MnO$ _{3} $/YBa$ _{2} $Cu$ _{3} $O$ _{7} $ (PLCMO/YBCO) multilayers the low temperature state of YBCO is very resistive and resembles the one of a granular superconductor or a frustrated…
The critical-state in a thin strip of YBaCuO is studied by magneto-optical imaging. The distribution of magnetic flux density is shown to have a specific symmetry in the remanent state after a large applied field. The symmetry was predicted…
Grain boundaries in YBa$_2$Cu$_3$O$_{7-x}$ superconducting films are considered as Josephson junctions with a critical current density $j_c(x)$ alternating along the junction. A self-generated magnetic flux is treated both analytically and…
We study here the spontaneous clustering of a submonolayer of grains under horizontal circular shaking. The clustering of grains occurs when increasing the oscillation amplitude beyond a threshold. The dense area travels in a circular…
Internal avalanches of grain displacements can be created inside a granular material kept in a bin in two ways: (i) By removing a radomly selected grain at the bottom of the bin (ii) By breaking a stable arch of grains clogging a hole at…
We are examining the possibility of the formation of charge order in the high-temperature superconductor $\mathrm{YBa_2Cu_3O_{7-\delta}}$ (YBCO) due to interaction between the charged oxygen vacancies or di-vacancies. The molecular dynamics…
The temperature dependence of AC susceptibility (ACS) has been measured for a very high-quality plate-like slightly overdoped YBCO single crystal for different frequencies and AC magnetic field amplitudes. Frequency dependence of the ACS is…
We consider the flux jump instability of the Bean's critical state arising in the flux creep regime in type-II superconductors. We find the flux jump field, $B_j$, that determines the superconducting state stability criterion. We calculate…