Superconducting wire and superconducting wire connection structure

A superconducting wire connection structure comprising:

• a first superconducting wire;
• a second superconducting wire;
• and
• a connection layer, wherein
• the first superconducting wire includes a first substrate, a first superconducting layer disposed on the first substrate, a first protective layer disposed on the first superconducting layer, and a first stabilization layer disposed on the first protective layer,
• the second superconducting wire includes a second substrate, a second superconducting layer disposed on the second substrate, a second protective layer disposed on the second superconducting layer, and a second stabilization layer disposed on the second protective layer,
• the first superconducting layer has a first surface facing the first substrate and a second surface opposite to the first surface,
• the second superconducting layer has a third surface facing the second substrate and a fourth surface opposite to the third surface,
• the first stabilization layer is connected to the second stabilization layer by the connection layer,
• the second surface has a portion having an arithmetic average roughness of 20 nm or more and a maximum height of 0.25 μm or more,
• the fourth surface has a portion having an arithmetic average roughness of 20 nm or more and a maximum height of 0.25 μm or more, and
• the maximum height of the portion of the second surface is measured by:
• (a) obtaining a first cross-sectional curve and a second cross-sectional curve from a measurement region included in the portion of the second surface, each of the first cross-sectional curve and the second cross-sectional curve having a sampling length;
• (b) obtaining a first maximum height of the portion of the second surface, the first maximum height of the portion of the second surface being a sum of a largest peak height and a largest valley depth obtained within the sampling length from the first cross-sectional curve from the measurement region included in the portion of the second surface;
• (c) obtaining a second maximum height of the portion of the second surface, the second maximum height of the portion of the second surface being a sum of a largest peak height and a largest valley depth obtained within the sampling length from the second cross-sectional curve from the measurement region included in the portion of the second surface, and
• (d) averaging the first maximum height of the portion of the second surface and the second maximum height of the portion of the second surface, and
• the maximum height of the portion of the fourth surface is measured by:
• (a) obtaining a first cross-sectional curve and a second cross-sectional curve from a measurement region included in the portion of the fourth surface, each of the first cross-sectional curve and the second cross-sectional curve having a sampling length;
• (b) obtaining a first maximum height of the portion of the fourth surface, the first maximum height of the portion of the fourth surface being a sum of a largest peak height and a largest valley depth obtained within the sampling length from the first cross-sectional curve from the measurement region included in the portion of the fourth surface;
• (c) obtaining a second maximum height of the portion of the fourth surface, the second maximum height of the portion of the fourth surface being a sum of a largest peak height and a largest valley depth obtained within the sampling length from the second cross-sectional curve from the measurement region included in the portion of the fourth surface, and
• (d) averaging the first maximum height of the portion of the fourth surface and the second maximum height of the portion of the fourth surface.