Related papers: The critical current density in type-II supercondu…
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…
The transport of electrical current through a superconductor falls into three broad regimes: non-dissipative, dissipative but superconducting, and normal or non-superconducting. These regimes are demarkated by two definitions of critical…
Novel behavior of the critical current density $j_{c}$ of a regularly perforated superconducting film is found, as a function of applied magnetic field $H$. Previously pronounced peaks of $j_{c}$ at matching fields were always found to…
One important factor affecting the critical current density in type-II superconductors is the formation of artificial pinning centers. Hence, the engineering of pinning centers in superconducting systems has garnered considerable attention.…
We present a comprehensive study of the critical current densities and the superconducting vortex phase diagram in the stoichiometric superconductor CaKFe$_4$As$_4$ which has a critical temperature of 35 K. We performed detailed…
A series of polycrystalline SmO1-xFxFeAs bulks (x=0.15, 0.2, 0.3 and 0.4) were prepared by the conventional solid state reaction. Resistivity, susceptibility, magnetic hysteresis, critical current density and microstructure of these samples…
An increasing current through a superconductor can result in a discontinuous increase in the differential resistance at the critical current. This critical current is typically associated either with breaking of Cooper-pairs (de-pairing) or…
The stability against quench is one of the main issue to be pursued in a superconducting material which should be able to perform at very high levels of current densities. Here we focus on the connection between the critical current $I_c$…
The addition of artificial pinning centers has led to an impressive increase in critical current density ($J_{\rm c}$) in a superconductor, enabling record-breaking all-superconducting magnets and other applications. $J_{\rm c}$ has reached…
We found that transport critical current density (Jc) of the Ba1-xKxFe2As2/Ag tapes is significantly enhanced by the combination process of cold flat rolling and uniaxial pressing. At 4.2 K, the Jc reaches a high value of 9.1x104 A/cm2 in 4…
In type-II superconductors, the magnetic field enters in the form of vortices; their flow under application of a current introduces dissipation and thus destroys the defining property of a superconductor. Vortices get immobilized by pinning…
We develop a general theory to account self-consistently for self-field effects upon the average transport critical current density Jc of a flat type-II superconducting strip in the mixed state when the bulk pinning is characterized by a…
The doping dependence of the critical current density, $J_{c}$, was measured in a series of high quality c-axis oriented ${\rm Bi_2Sr_2CaCu_2O_{8+\delta}}$ thin films. For each doping level we measured the temperature dependence of $J_{c}$.…
A series of doping experiments are reported for MgB2 conductors that have been synthesized using doped boron fibers prepared by chemical vapor deposition(CVD) methods. Undoped MgB2 samples prepared from CVD prepared fibers consistently give…
We show results on the vortex core dissipation through current-voltage measurements under applied pressure and magnetic field in the superconducting phase of CeCoIn$_5$. We find that as soon as the system becomes superconducting, the vortex…
The critical current density of four MgB2 samples was measured inductively and for one of them also by transport. Pure phased and dense bulk samples yield a critical current density which in value, as well as in its magnetic field and…
We measured the critical temperatures and critical switching and retrapping currents of wide and narrow thin-film quasi-one-dimensional superconducting aluminum structures of the same thickness in zero magnetic field. For the first time, we…
The dynamics of vortices in a type-II superconductor with defects are studied by solving the time-dependent Ginzburg-Landau equations in two and three dimensions. We show that vortex flux tubes are trapped by volume defects up to a critical…
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…
The pair-breaking critical current density j_{d} of magnesium diboride was determined over its entire temperature range by a pulsed dc transport measurement. At fixed low values of current density j, the resistive transition temperature Tc…