Related papers: Inter- and intragrain currents in bulk melt-grown …
We present a magnetization study of low density YBCO ceramics carried out in magnetic fields 0.5 Oe < H < 50 kOe. It was demonstrated that superconducting links between grains may be completely suppressed either by a magnetic field of the…
The determination of the critical current density from magnetic hysteresis loops is widely used to characterize and compare superconducting samples. Magnetic hysteresis loops for tapes and single crystals depend on both the critical current…
Scanning transmission x-ray microscopy has been used to image electric currents in superconducting films at temperatures down to 20 K. The magnetic stray field of supercurrents in a thin YBaCuO film is mapped into a soft-magnetic coating of…
The critical current density of a superconducting film can be easily determined by an inductive and contactless method. Driving a sinusoidal current in a single coil placed in front of a superconducting sample, a non zero third harmonic…
The trapped magnetic field is examined in bulk high-temperature superconductors that are artificially drilled along their c-axis. The influence of the hole pattern on the magnetization is studied and compared by means of numerical models…
The authors report magnetic measurements of fluxoid transitions in mesoscopic, superconducting aluminum rings. The transitions are induced by applying a flux to the ring so that the induced supercurrent approaches the critical current. In a…
A study of magnetic flux penetration in a superconducting film patterned with arrays of micron sized antidots (microholes) is reported. Magneto-optical imaging (MOI) of a YBCO film shaped as a long strip with perpendicular antidot arrays…
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…
A systematic study of I-V characteristic curves for RuSr2GdCu2O8 [Ru-(1212)] is presented, with magnetic fields up to 3 T and 5 K<T<30 K, in the region of the superconducting transition. The activation energy E_{a}(H,T) for flux line…
We show that low-angle grain boundaries (GB) in high-temperature superconductors exhibit intermediate Abrikosov vortices with Josephson cores, whose length $l$ along GB is smaller that the London penetration depth, but larger than the…
The influence of the bulk density of YBa2Cu3-xFexOy (0 < x < 0.01) ceramics on the intergranular superconducting (SC) properties was studied using the temperature dependence of AC magnetic susceptibility measurements. It was found that the…
The magnetic coupling between two concentric mesoscopic superconductors with non-zero thickness is studied using the nonlinear Ginzburg-Landau theory. We calculated the free energy, the expelled field, the total field profile, the…
We employed a scanning Hall probe microscope to detect the hopping of individual vortices between pinning sites along grain boundaries in YBCO thin films in the presence of an applied current. Detecting the motion of individual vortices…
An analysis of the influences of a high frequency (30 kHz) alternating current on the uniformity of the magnetic field (B) in an electromagnetic casting (EMC) mould is investigated by means of parametric numerical simulations where the…
Magnetic measurements carried out on MgB_2 superconducting round wires have shown that the critical current density J_c(B_a) in wires sheathed by iron can be significantly higher than that in the same bare (unsheathed) wires over a wide…
We have studied the remanent magnetic flux distribution in bulk melt-textured YBa2Cu3O7 (YBCO) crystals after their magnetization in quasi-static and pulsed magnetic fields up to 6T. It has been shown that, provided that the magnetic pulse…
The critical current (Jc) of highly twinned YBa2Cu3O7 films has been measured as a function of temperature, magnetic field and angle. For much of the parameter space we observe a strong suppression of Jc for fields in the twin boundary (TB)…
The discovery of superconductivity at 39 K in MgB2[1] raises many issues. One of the central questions is whether this new superconductor resembles a high-temperature-cuprate superconductor or a low-temperature metallic superconductor in…
We have measured the dynamics of individual magnetic fluxoids entering and leaving thin film, photolithographically patterned rings of underdoped high-temperature superconductor BSCCO using a variable sample temperature scanning SQUID…
A rapid decrease in the critical current density (Jc) of YBa2Cu3O7-x (YBCO) films with increasing film thickness has been observed for multiple YBCO growth processes. While such behavior is predicted from 2D collective pinning models under…