Co-Doped BaFe2As2 Superconducting Nanowires for Detector Applications

Nanowires of Co-doped BaFe
₂
As
₂
have been realized and characterized. Thin films having thickness of 20 nm were grown on CaF
₂
(100) substrates by pulsed laser deposition. The films were then passivated in situ with a thin layer of MgAl
₂
O
₄
. Using electron beam lithography, several submicron nanowire structures were patterned and electrically contacted to gold pads. The nanostructures have a superconducting critical temperature T of 16 K, for a 500-nm-wide nanowire, and properties, in terms of normal state resistivity (0.3 mΩ·cm) and critical current (1 MA/cm
₂
at 3 K), comparable with those of NbN nanowires. Moreover, they show localization effects in the normal state, while the current-voltage characteristics are dominated by flux creep.