Apparatus and systems comprising a clad superconductive oxide body, and method for producing such body

A method of producing clad superconductive oxide wire (10), tape and the like is disclosed. The method comprises forming an intermediate body by surrounding a quantity of the oxide powder (e.g., Ba2YCu3O6.9) with an appropriate cladding material (typically normal metal), reducing the cross section of the intermediate body by an appropriate technique (e.g., drawing or rolling), and heat treating the elongated body such that substantial sintering of the powder results, such that, after completion of the heat treatment, the sintered oxide (11) has a composition that is associated with superconductivity in unclad bulk samples of the oxide, and such that the body manifests superconductivity at a temperature above about 77K. These conditions require that at least the portion of the cladding that is in contact with the oxide powder is substantially inert with respect to oxygen and the oxide under the conditions of the heat treatment, and that at least a portion of the oxide is in contact with an effective concentration of oxygen during at least a part of the heat treatment such that the oxide powder can take up oxygen. Silver is the currently preferred inert normal metal. Exemplarily, Ag can be used to provide a diffusion barrier (13), with other normal metal (e.g., Ni (14) and Cu (15)) surrounding the diffusion barrier, or the cladding can consist substantially of Ag. Various techniques for preventing oxygen loss and/or restoring lost oxygen from the powder are disclosed. Advantageously the elongated body is appropriately shaped (e.g., wound into a helical coil) prior to completion of the heat treatment. Elongate bodies produced according to the invention can advantageously be used as superconductive magnets, and in a variety of other apparatus and systems.