a b Plane Point Contact Spectroscopy measurements of optimally Cobalt doped Ba-122 iron-pnictide superconductors

摘要: Point contact spectroscopy (PCS) is a technique which can reveal the size and symmetry of superconducting gap (�) especially useful for new materials such as iron-based superconductors. PCS usually employed in conjunction with extended Blonder-Tinkham-Klapwijk (BTK) model used to extract information existence nodes infrom data obtained on unconventional The BTK uses dimensionless parameter Z quantify barrier strength across normal metal - superconductor junction. We have unique feature allows variation obtain crucial about �. report our Z-dependent, b plane measurements single crystals BaFe2 xCoxAs2. Our show that xCoxAs2 (x=0.148) two gaps does not contain any nodes. dependent point spectra rule out pure d at optimal doping negligible anisotropy.