Mgb2 superconductive thin film wire material and production method therefor

A production method for an MgB2 superconductive thin film wire material, the MgB2 superconductive thin film wire material including:

• a long metal substrate;
• and an MgB2 thin film formed on the long metal substrate, wherein:
• the MgB2 thin film has a critical temperature of 30 K or higher, and has a microscopic organization in which MgB2 columnar crystal grains densely stand on a surface of the long metal substrate and an Mg oxide layer is formed in such a manner as to surround the MgB2 columnar crystal grains in a grain boundary region of the MgB2 columnar crystal grains,
• the method comprises an MgB2 thin film forming step of forming the MgB2 thin film on the long metal substrate by a co-evaporation method under a predetermined temperature condition in a predetermined vacuum atmosphere;
• the predetermined vacuum atmosphere is controlled so as to contain a highly oxidative gas in a partial pressure range of 0.05% or more and 0.2% or less of an Mg vapor partial pressure during deposition;
• and
• in the predetermined temperature condition, a temperature of the long metal substrate is controlled to 250° C. or higher and 300° C. or lower.