A cylindrical Josephson junction with a spatially dependent Josephson coupling which averages to zero is studied in order to model the physics of a disk of d-wave superconductor embedded in a superconducting film of a different symmetry. It is found that the system always introduces Josepshon vortices in order to gain energy at the junction. The critical current is calculated. It is argued that...

We report the far-infrared properties of superconducting ab plane-oriented YBa2Cu3O7-d films in magnetic fields of up to 27 T. The applications of magnetic field (with H perpendicular to the ab plane and with unpolarized light) at low temperature produces no discernible field dependence. This observation differs from other previous far-infrared measurements in this temperature range. Only at fi...

We report measurements of the flux hysteresis curves and trapped flux distribution in an YBa2Cu3O7 r.f. SQUID containing two closely spaced grain boundary Josephson junctions in parallel. Broadening of the flux distribution from T = 15 K to 30 K is followed by a bifurcation at T = 35 K which corresponds to a degenerate ground state. Above T ≈ 40 K the bifurcation disappears, the flux distributi...

Here we study the electronic properties of cuprate-manganite interfaces. By means of atomic resolution electron microscopy and spectroscopy, we produce a subnanometer scale map of the transition metal oxidation state profile across the interface between the high Tc superconductor YBa2Cu3O7-δ and the colossal magnetoresistance compound (La,Ca)MnO3. A net transfer of electrons from manganite to c...

A study has been perfomed on the superconducting critical current density Jc flowing across low angle grain boundaries in epitaxial thin films of YBa2Cu3O7−δ (YBCO). The materials studied were dual grain boundary rings deposited on SrTiO3 and containing 2 , 3, 5 and 7 tilt boundaries. The current density in self-field was determined by magnetometric methods at temperatures from 5 K to Tc. We co...

We have studied the angular dependence of the irreversible magnetization of several YBa2Cu3O7 and 2H-NbSe2 single crystals with columnar defects tilted off the c axis. At high magnetic fields, the irreversible magnetization M i(Q) exhibits a well-known maximum when the applied field is parallel to the tracks. As the field is decreased below H;0.02Hc2, the peak shifts away from the tracks’ direc...

We examine the anomalous inverse spin switch behavior in La0.7Ca0.3MnO3(LCMO)/YBa2Cu3O7-δ (YBCO)/LCMO trilayers by combined transport studies and polarized neutron reflectometry. Measuring magnetization profiles and magnetoresistance in an in-plane rotating magnetic field, we prove that, contrary to many accepted theoretical scenarios, the relative orientation between the two LCMO's magnetizati...

Various techniques have been applied to visualize superconducting vortices, providing clues their electromagnetic response. Here, we present a wide-field, quantitative imaging of the stray field vortices in thin film using perfectly aligned diamond quantum sensors. Our analysis, which mitigates influence sensor inhomogeneities, visualizes magnetic flux single YBa2Cu3O7−δ with an accuracy ±10%. ...

In this study, High temperature superconductor YBa2Cu3O7-x (YBCO) nanoparticle was prepared by Sol-gel technique. The sol-gel includes a homogeneous solution of Y-Ba-Cu acetate precursor and acetic acid. powder compressed hydraulic at 5 ton/cm2 needed post-reaction heat treatment 850 °C for 8 h with oxygen flow. YBCO bulk has been characterized using traditional R-T measurements, producing best...