Transport measurement of MgB2 wire under the sub-cooled water ice compared to other cooling conditions

The standard DC transport measurements of MgB2 composite conductors were done in vacuum, low-pressure helium gas, sub-cooled solid nitrogen and water ice. The effect of these coolants on electro-thermal behaviour was studied at self-field and temperature range from 32 K to 36.5 K. The obtained results show that even small volume of Helium gas enhances the sample thermal stability during the I-V measurement in comparison to those obtained in vacuum. The cooling by solid nitrogen improves the sample stability in contrast to helium gas. The measurements performed inn water ice exhibits an excellent and stable behavior of superconducting wire carrying high transport current below and above the quench as well. Consequently, water ice shows simple, safe, and promising He-free mode of cooling for future superconducting systems.