Synthesis of Bi2Sr2CaCu2Oy nanowire and its superconductivity

The superconducting Bi2Sr2CaCu2Oy nanowires were synthesized by a sol–gel template route in a porous anodic aluminum oxide (AAO) membrane. Field emission scanning electron microscopy (FESEM) confirmed that the monodisperse cylindrical pores of alumina membrane were filled with superconducting nanowire arrays. The nanowires were essentially polycrystalline as determined by high resolution transmission electron microscope (HRTEM) images and selected electron diffraction (SAED) analysis. The onset transition temperature of the Bi2Sr2CaCu2Oy nanowires is 84K, which is close to the transition temperature of bulk material. The superconducting hysteresis loop measurement indicates that the critical current density decreases with increasing applied magnetic field and temperature.