We use electromigration (EM) to tune the oxygen content of YBa$_2$Cu$_3$O$_{7-\delta}$ (YBCO) nanowi\-res. During EM, dopant atoms in nanowire are moved under combined effect electrostatic force and Joule heating. The EM current can be tuned either deplete or replenish nanowires with oxygen, allowing fine tuning its hole doping level. Electrical transport measurements Kelvin probe microscopy co...

This article presents results from a simple experimental methodology used to determine the amount of heat transferred an yttrium barium copper oxide (YBCO) bulk liquid nitrogen (LN2) and LN2 consumption during process zero-field cooling (ZFC). The thermal power can be determined YBCO temperature variation, which is difficult measure with accuracy. In this procedure, measured rate evaporation, c...

A model for superstructure ordering in the « chain » layers of Ga (Co) substituted YBCO intergrowths with gencral formula (REO~)NSr~MCU~O~ (M = Co, Ga

YBa2Cu3O7−x (YBCO) coated conductors are realized by the deposition of a YBCO film atop thin (10−6 m) ceramic buffer layers, previously deposited upon a high resistance nickel alloy. On the other side of the tape a copper layer is often added to create an alternative current path during quenches. Several investigations have shown a different qualitative behaviour of the voltages measured on the...

A comprehensive study of the dc and rf electrodynamic properties of YBa 2 Cu 307-, (YBCO) thin films, grain boundaries and Josephson junctions (JJ) is presented. The surface impedance Z, = R, + iX, of YBCO thin films is shown to have a dependence on rf current, which leads to nonlinear power losses at levels of rf power that are relevant for device applications. To understand the loss mechanism...

Doping of YBa2Cu3O7-δ (YBCO) has become an effective means of increasing the flux pinning and critical current densities (Jc) in thin film superconductors, while maintaining the transition temperature (Tc). In previous research efforts, our group showed that doping (Y1xREx)BCO with typically deleterious rare earth (RE) elements can be used to improve the film’s current density via flux pinning ...

YBCO thin films have been grown by Metal Organic Chemical Vapour Deposition in ;I cold wall type reactor. The 0-diketonates of yttrium, barium and copper are used as precursors. Filrna have bcen deposited on (001 I MgO and (012) LaA103 single crystalline substrates. The morphology is very dependant on thc gas p h a x composition. Different oxygen partial pressures have been investigated. An inc...

We have implemented coherent gradient sensing (CGS) as an in-situ diagnostic in an MOCVD reactor to measure curvature and changes in curvature with varying temperature and O2 partial pressure on thin ̄lm YBCO on MgO (001) substrates. CGS is a novel, real-time, full̄eld optical technique that provides a direct map of the components of the curvature tensor across the surface of the wafer. We have ...