Magnesium Diboride Flexible Flat Cables for Cryogenic Electronics

Magnesium diboride (MgB
₂
) thin films are a potential alternative to low-temperature superconductors (LTS) due to a higher critical temperature (
Tc
) of approximately 39 K. The reactive evaporation deposition technique also affords relatively simple growth of MgB
₂
films on flexible substrates compared to high-temperature superconductors (HTS). We have designed and fabricated a cable architecture consisting of MgB
₂
traces on flexible yttria-stabilized zirconia (YSZ) compatible with commercially available connectors or direct wirebonds. Key performance metrics such as critical current density (
Jc
) and
Tc
are measured and compared. We discuss thermal conductivity and passivation schemes for these cables.