APS -APS March Meeting 2017 - Event - Normal and superconducting properties of Co--doped BaFe$_{mathrm{2}}$As$_{mathrm{2}}$ and MgB$_{mathrm{2}}$ thin films after He ion irradiation

摘要

We have investigated the normal and superconducting properties of Co-doped BaFe$_{mathrm{2}}$As$_{mathrm{2}}$ (Ba122) and MgB$_{mathrm{2}}$ bridges irradiated at room temperature using a 30 kV He$+$ beam (ZEISS Orion Plus Helium ion microscope) and doses between 10$^{mathrm{13}}$--10$^{mathrm{17}}$/cm$^{mathrm{2}}$. Our results show that the critical temperature of irradiated region reduces to extless 2K for doses extgreater 3x10$^{mathrm{14}}$/cm$^{mathrm{2}}$ for Ba122 and extasciitilde 1x10$^{mathrm{16}}$/cm$^{mathrm{2}}$ for MgB$_{mathrm{2}}$ films. All the samples show a consistent increase in the resistivity of irradiated region with the increase in the beam dose. Furthermore, irradiated Ba122 becomes insulating at high enough dose (6x10$^{mathrm{16}}$/cm$^{mathrm{2}})$ while MgB$_{mathrm{2}}$ remains metallic at all doses used. This result for Ba122 allows us to fabricate planar SIS Josephson junction in this material; RSJ-like behavior and typical critical voltages I$_{mathrm{c}}$R$_{mathrm{n}}$ of 400 $mu$ V are seen at 10 K.