相关论文: Self-field effects upon the critical current densi…
Recent theoretical and experimental research on low-bulk-pinning superconducting strips has revealed striking dome-like magnetic-field distributions due to geometrical edge barriers. The observed magnetic-flux profiles differ strongly from…
Mechanisms of vortex dynamics and pinning and self-field effects which could account for the thickness dependence of the critical current density J_c of superconducting films are addressed. It is shown that at low magnetic fields B, the 2D…
A current-carrying superconducting strip partly penetrated by magnetic flux and surrounded by a bulk magnet of high permeability is considered. Two types of samples are studied: those with critical current controlled by an edge barrier…
We report on the thickness dependence of the superconducting characteristics including critical current Ic, critical current density Jc, transition temperature Tc, irreversibility field Hirr, bulk pinning force plot Fp(H), and the normal…
Detailed measurements of the critical current density jc of YBa2Cu3O7 films grown by pulsed laser deposition reveal the increase of jc as function of the filmthickness. Both this thickness dependence and the field dependence of the critical…
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…
Transport characteristics of nano-sized superconducting strips and bridges are determined by an intricate interplay of surface and bulk pinning. In the limiting case of a very narrow bridge, the critical current is mostly defined by its…
A series of polycrystalline SmFeAs1-xOx bulks was prepared to systematically investigate the influence of sample density on flux pinning properties. Different sample densities were achieved by controlling the pelletizing pressure. The…
Although the flux density map of a bulk superconductor provides in principle sufficient information for calculating the magnitude and the direction of the supercurrent flow, the inversion of the Biot-Savart law is ill conditioned for thick…
The critical state in a superconducting thin circular disk with an arbitrary magnetic field dependence of the critical sheet current, Jc(B), is analyzed. With an applied field Ba perpendicular to the disk, a set of coupled integral…
We discuss predictions of five proposed theories for the critical state of type-II superconductors accounting for both flux cutting and flux transport (depinning). The theories predict different behaviours for the ratio $E_y/E_z$ of the…
An exact analytical solution is given for the critical state problem in long thin superconductor strips in a perpendicular magnetic field, when the critical current density j_c(B) depends on the local induction B according to a simple…
Numerical simulations of the current and field distribution in thin superconducting films are carried out for a given material law Jc(B) and as a function of the applied field H, taking the sample's self-field into account. The dependence…
We report DC isothermal magnetization, global critical current density (JC), Intra-grain critical current density (JCintra) and resistive upper critical field (Bc2) of polycrystalline Y1-xCaxBa2Cu3O7-{\delta} (YBCO); x = 0.00, 0.05, 0.10,…
We calculate the magnetic-field dependence of the critical current due to both geometrical edge barriers and bulk pinning in a periodic coplanar array of narrow superconducting strips. We find that in zero or low applied magnetic fields the…
We have studied the local critical current density, jc, in the superconductor thin film of bilayer structures consisting of YBa2Cu3O7 and the ferromagnets La2/3Ca1/3MnO3 and SrRuO3, respectively, by means of quantitative magneto-optics. A…
A study has been perfomed on the superconducting critical current density J_{c} flowing across low angle grain boundaries in epitaxial thin films of YBa{2}Cu{3}O{7-d} (YBCO). The materials studied were dual grain boundary rings deposited on…
Flux pinning scaling laws were developed to explain the observed increase in the critical current density Jc caused by increased density of grain boundaries in polycrystalline low temperature superconductors (LTS) such as Nb3Sn. For four…
The critical current density Jc in high-Tc superconductors (HTS) often shows a maximum at field far above the self-field. We study this peak effect(PE) with the nonlinear I-V response of type-II superconductors and find analytical equation…
Superconducting critical currents $j_{c} > 10^{5}$ A/cm$^{2}$ at temperatures $T \sim 50$ K and magnetic fields $B \sim 6$ T are reported for the YBa$_{2}$Cu$_{3-x}$Mo$_{x}$O$_{7+d}$ compound with $x = 0.02$. Clear evidence for the…