Large, single grain (RE)BCO superconductors for high magnetic field and microwave device applications

(RE)-Ba-Cu-O bulk high temperature superconductors (HTS) have the potential to generate large magnetic fields for use in stable magnetic field'bearings, flywheel energy storage systems and permanent magnet devices. For this purpose it is necessary to fabricate large, grain-boundary free bulk (RE)BCO materials. I propose here to fabricate large single grain superconductors with high trapped fields and evaluate their properties specifically for engineering applications. A detailed study of the seeing process, basic growth conditions for various (RE)BCO pseudo-single crystals and optimisation c fundamental processing parameters for various (RE)BCO systems will be carried out. In addition, study on theenhancement of the current density and the irreversibility filed of (RE)BCO single grains by engineering the microstructure, altering the carrier concentration and introduction of natural and artificial pinning centers to the bulk superconducting matrix will be carried out. The results obtained in this research work will be used to fabricate large single grain superconductors with very large trapped fields. Joining of the individual single grains is necessary for complex shaped superconductors, for specific medical and engineering applications and it is proposed in this work to develop effective joining process for HTS for this purpose. Current technologies for the fabrication of materials for HTS microwave applications have been based primarily on thin films. These thin film devices are limited to relatively simple microwav filter geometries and require sophisticated equipment for their deposition. We propose here to fabricate microwave resonators and filters of more complex geometries with low surface resistance from bulk superconductors. It is envisaged that this will enable fabrication of low cost, mass produced 3-D devices.