Phase-Sensitive measurements on the corner junction of iron-based superconductor BaFe1.8Co0.2As2

We have made a phase-sensitive measurement on the corner junction of the iron-based superconductor BaFe1.8Co0.2As2, and observed the typical Fraunhofer-like diffraction pattern. The result suggests that there is no phase shift between the a-c face and b-c face of a crystal, which indicates that the superconducting wavefunction of the iron based superconductor is different from that of a cuprate superconductor.