Local transport characteristics of break junction in Sr2RuO4 microbridge

We have measured tunnel conductance of spin-triplet superconductor Sr2RuO4 (SRO) break junction which was made by micro fabrication technique with a focused ion beam. This is a new type of tunnel junctions made of SRO, which is different from those made of SRO and other materials. Since the tunnel conductance is sensitive to the internal phase of superconductivity, it enables us to examine the chiral p-wave pairing state, which is the most probable candidate of SRO. The tunnel conductance spectrum of the junction showed a broad zero-bias conductance peak whose shape is different from that of high-T-c cuprate superconductors. The shape of the spectrum is in quite good agreement with the calculated spectrum of a chiral p-wave/insulator/normal metal junction. (C) 2011 Elsevier B.V. All rights reserved.