Related papers: Intergrain current flow in a randomly oriented pol…
Transport critical current (Ic) was measured for Fe-sheathed MgB2 round wires. A critical current density of 5.3 x 10^4 A/cm^2 was obtained at 32K. Strong magnetic shielding by the iron sheath was observed, resulting in a decrease in Ic by…
We have systematically investigated the grain boundary (GB) angle dependence of transport properties for NdFeAs(O,F) fabricated on [001]-tilt symmetric MgO bicrystal substrates. In our previous study, NdFeAs(O,F) bicrystal films showed a…
The AC susceptibility at zero DC magnetic field of a polycrystalline sample of LaFeAsO_{0.94}F_{0.06} (T_c = 24 K) has been investigated as a function of the temperature, the amplitude of the AC magnetic field (in the range Hac = 0.003 - 4…
A narrow intragrain phase-lock transition was observed in RuSr2EuCu2O8 under a magnetic field H up to a few Tesla. The corresponding transition temperature, T2, decreases rapidly (about 100 K/T at low fields) with H indicating that the…
We present a set of experimental results concerning the power spectrum of current noise, detected on a granular high Tc superconductor submitted either to a slowly varying magnetic field or to a varying current intensity. Experiments were…
Ion transport in solid-state devices is of great interest for current and future energy and information technologies. A superior enhancement of several orders of magnitude of the oxygen diffusivity has been recently reported for grain…
Magnetic flux distribution across a high-temperature superconductor strip is measured using magneto-optical imaging at 15 K. Both the current-carrying state and the remanent state after transport current are studied up to the currents 0.97…
A systematic study of the weak- link behavior for YBa2Cu3O7-d polycrystalline samples has been done using the electrical resistivity and AC susceptibility techniques.The experiments were performed with two samples of similar grain, a sample…
Grain boundary bicrystal Josephson junctions of the electron-doped infinite-layer superconductor Sr$_{1-x}$La$_x$CuO$_2$ ($x = 0.15$) were grown by pulsed laser deposition. BaTiO$_3$-buffered $24\,^\circ$ [001]-tilt symmetric SrTiO$_3$…
The intergranular pinning potential U and the critical current density Jc for polycrystalline RuSr2Gd1.5Ce0.5Cu2O10 ruthenate-cuprate were determined at zero magnetic field and temperature through the frequency shift in the peak of the…
The lower critical field of the grains, $H_{c1}$, and the intragrain critical current density, $J_{c}$, were determined for the superconducting ruthenate-cuprate RuSr$_{2}$Gd$_{1.5}$Ce$_{0.5}$Cu$_{2}$O$_{10-\delta}$ [Ru-1222(Gd)] through a…
We investigated the magnetization and crystal structure of FeSe polycrystalline samples with various grain sizes. For the samples with large grains, a large magnetic critical current density Jc was observed. For the samples with small…
The critical current density flowing across low angle grain boundaries in YBa$_2$Cu$_3$O$_{7-\delta}$ thin films has been studied magnetometrically. Films (200 nm thickness) were deposited on SrTiO$_3$ bicrystal substrates containing a…
A series of SmFeAsO1-xFx (Sm1111) bulk samples (x = 0.05 to 0.40) are synthesized by an in-situ cubic-anvil high-pressure technique at 4 GPa and systematically characterized through structural, microstructural, Raman, transport, and…
There are processes in nature that resemble a true force but arise due to the minimization of the local energy. The most well-known case is the exchange interaction that leads to magnetic order in some materials. We discovered a new similar…
The Fe-based superconductors (FBS) are an important new class of superconducting materials. As with any new superconductor with a high transition temperature and upper critical field, there is a need to establish what their applications…
The superconducting current has been observed in mesa-heterostructures Nb/Au/Sr2IrO4/YBa2Cu3Ox with Sr2IrO4 interlayer thickness d=5 and 7 nm and in-plane sizes L=10-50 mcm. A strontium iridate, Sr2IrO4, is known as a canted…
The c-axis textured Sr1-xKxFe2As2 tapes produced by cold rolling and post-annealing, could carry a high super-current over 2*104 A/cm2. However, the magnitude is far from its maximum, because of the current obstacles associated with various…
Grain boundaries are critical for determining the functionality of polycrystalline materials. Here we present on the structural $\&$ transport properties of grain boundaries in the unconventional superconductor CeCoIn$_5$. We provide a…
Macroscopic current uniformity in a (Ba,K)Fe2As2 bulk sample produced by a process that demonstrated high trapped magnetic fields was evaluated through a comparative experimental and modeling approach. The bulk sample, with a well-defined…