Related papers: The critical current density in type-II supercondu…
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 method is proposed for estimating the length scale of currents circulating in superconductors. The estimated circulation radius is used to determine the critical current density on the basis of magnetic measurements. The obtained formulas…
We analyze the influence of the magnetic field generated by the supercurrents (self-field) on the current density distribution by numerical simulations. The thickness of the superconducting film determines the self-field and consequently…
Strongly disordered superconductors in a magnetic field display many characteristic properties of type-II superconductivity--- except at low temperatures where an anomalous linear $T$-dependence of the resistive critical field $B_{c2}$ is…
Quantitative magneto-optical imaging of a type-II superconductor thin film cooled under zero, homogeneous, and inhomogeneous applied magnetic fields, indicates that the latter procedure leads to an enhancement of the screening capacity.…
As superconductors are thinned down to the 2D limit, their critical temperature $T_c$ typically decreases. Here we report the opposite behavior, a substantial enhancement of $T_c$ with decreasing thickness, in 2D crystalline superconductor…
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…
We report on measuring the depairing current J_{dp} in thin superconducting films as a function of temperature. The main difficulties in such measurements are that heating has to be avoided, either due to contacts, or to vortex flow. The…
Transport measurements of critical current density, Jct, in monocore powder-in-tube MgB2 strands have been carried out at temperatures, T, of from 4.2 K to 40 K, and in transverse fields, B, of up to 14 T. Processing methods used were…
A simple approach to describe the levitation force measurements on melt-processed HTS bulks was developed. A couple of methods to determine the critical current density $J_c$ were introduced. The averaged $ab$-plane $J_c$ values for the…
In the search for new physical properties of S/F structures, we have found that the superconductor critical current can be controlled by the domain state of the neighboring ferromagnet. The superconductor is a thin wire of thickness d_{s} ~…
The determination of their critical current density in the whole range of the temperature below Tc is of first importance to understand the physical processes occurring in superconducting films. We describe here a technique suitable for…
The superconducting critical current density, Jc, in hole doped cuprates show strong dependence on the doped hole content, p, within the copper oxide plane(s). The doping dependent Jc mainly exhibits the variation of the intrinsic depairing…
Transverse ac permeability measurements in Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta }$ single crystals at low fields and temperatures in a vortex configuration free of external forces show that the decrease of the critical current as measured by…
Large area arrays of through-thickness nanoscale pores have been milled into superconducting Nb thin films via a process utilizing anodized aluminum oxide thin film templates. These pores act as artificial flux pinning centers, increasing…
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…
We theoretically investigate the response of a superconducting film to line currents flowing in linear wires placed above the film, and we present analytic expressions for the magnetic-field and current distributions based on the critical…
Critical current measurements were made on thin films of YBa2Cu3O7-delta and Y0.8Ca0.2Ba2Cu3O7-delta produced by sol-gel and pulsed laser deposition, respectively. Both samples have high critical currents at low temperatures and the…
We report on transport and magnetization measurements of the critical current density Jc in ErNi2B2C single crystals that show strongly enhanced vortex pinning at the Neel temperature TN and low applied fields. The height of the observed Jc…
Starting from the temperature dependence of the energy density and pressure from lattice QCD calculation, we extract the temperature dependence of the electric and magnetic condensate near $T_c$. While the magnetic condensate hardly changes…