Superconducting cuprates grain boundaries

For the development of applications for superconductors, two obstacles in particular have to be surmounted. The first is that the material must be cooled to low temperatures to attain 7),. As higher temperature superconductors are developed, this has become less of a major drawback, but still militates against the use of superconductors in conventional settings. The second problem is one of fabrication. When prepared as a bulk material, the cuprate superconductors have unacceptably low critical current densities, i.e. the superconductivity is lost after the material has carried only a limited amount of current. The origin of the problem is the presence of grain boundaries in the solid... 

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