Patent ID: 8238991

Claim:
A precursor wire of an oxide superconducting wire, the precursor wire comprising: (a) a first sheath made of silver or silver alloy; (b) a center portion placed at the inside of the first sheath; and (c) a plurality of peripheral segments placed close to one another at the inside of the first sheath so as to surround the center portion; in the center portion, a monofilamentary segment being placed, the monofilamentary segment having a circular or regular hexagonal cross section and comprising a filament made of a precursor of an oxide superconductor and covered with a second sheath made of silver or silver alloy; each of the multiple peripheral segments being formed as a monofilamentary segment that has an arch-shaped cross section and that comprises a ribbon-shaped filament made of a precursor of an oxide superconductor and covered with a second sheath made of silver or silver alloy; the multiple peripheral segments being placed in a multilayer state in the form of concentric circles such that wide-width surfaces of the peripheral segments surround the center portion.