Substrate for oxide superconductor and process for producing same, and oxide superconductor and process for producing same

A substrate for an oxide superconductor comprising:

• a metal base;
• an interlayer of MgO formed on the metal base by ion beam assisted deposition method (IBAD METHOD);
• and
• a cap layer that is formed directly on the interlayer and has a higher degree of crystal orientation than that of the interlayer,
• wherein a hydroxide of Mg exists in the interface between the interlayer of MgO and the cap layer.

A process for producing a substrate for an oxide superconductor comprising:

• a metal base;
• an interlayer of MgO formed on the metal base by ion beam assisted deposition method (IBAD METHOD);
• and a cap layer that is formed directly on the interlayer and has a higher degree of crystal orientation than that of the interlayer, the process for producing a substrate for an oxide superconductor comprising:
• forming a laminate by forming the interlayer of MgO on the metal base;
• performing a humidity treatment on the laminate;
• and
• forming the cap layer directly on the interlayer of MgO.