Improvement in critical current density for oxide superconductors.

Hysteresis in Transport Critical-Current Measurements of Oxide Superconductors

We have investigated magnetic hysteresis in transport critical-current (I c) measurements of Ag-matrix (Bi,Pb)2Sr2Ca2Cu3O10- x (Bi-2223) and AgMg-matrix Bi2Sr2CaCu2O8+ x (Bi-2212) tapes. The effect of magnetic hysteresis on the measured critical current of high temperature superconductors is a very important consideration for every measurement procedure that involves more than one sweep of magn...

Upper Critical Field for Cobalt Oxide Superconductors

Motivated by the recent discovery of the cobalt oxide superconductors, we calculate the temperature dependence of the upper critical field on a triangular lattice. Using the lattice version of the Gor’kov equations we investigate how the applied magnetic field affects singlet and triplet types of superconductivity. We show that in a wide range of model parameters not only Zeeman coupling, but a...

Anomalous superfluid density in quantum critical superconductors.

When a second-order magnetic phase transition is tuned to zero temperature by a nonthermal parameter, quantum fluctuations are critically enhanced, often leading to the emergence of unconventional superconductivity. In these "quantum critical" superconductors it has been widely reported that the normal-state properties above the superconducting transition temperature T(c) often exhibit anomalou...

Effect of sample size on the magnetic critical current density in nano-SiC doped MgB2 superconductors

Sample-size dependence of the magnetic critical current density in MgB2 superconductors