Fabrication of superconducting nanowires from ultrathin MgB2 films via focused ion beam milling

High quality superconducting nanowires were fabricated from ultrathin MgB2 films by a focused ion beam milling technique. The precursor MgB2 films in 10 nm thick were grown on MgO substrates by using a hybrid physical-chemical vapor deposition method. The nanowires, in widths of about 300-600 nm and lengths of 1 or 10 mu m, showed high superconducting critical temperatures (T-c's) above 34 K and narrow superconducting transition widths (Delta T-c's) of 1-3 K. The superconducting critical current density J(c) of the nanowires was above 5 x 107 A/cm(2) at 20 K. The high T-c, narrow Delta T-c, and high J(c) of the nanowires offered the possibility of making MgB2-based nano-devices such as hot-electron bolometers and superconducting nanowire single-photon detectors with high operating temperatures at 15-20 K. (C) 2015 Author(s).