Search for order parameter domains in single crystal flakes of chiral $p$-wave superconductor Sr$_2$RuO$_4$ using micrometer size Josephson junctions

Even though the odd-parity, spin-triplet superconductivity in Sr$_2$RuO$_4$ is supported by many experimental studies, the existence of order parameter domains and domain walls remains to be an open question. In addition, how these domains can be controlled experimentally is not understood. We fabricate small Al-Sr$_2$RuO$_4$ Josephson junctions using flakes of singlecrystalline Sr$_2$RuO$_4$ prepared by mechanical exfoliation, using Ti as an interlayer for adhesion purpose. The 3 $\mu$m wide junctions defined by photolithography on a natural $ac$ plane was found to show Josephson coupling. Experiments on the effect of domain walls on Josephson coupling and the control of domain walls are being explored. The work is supported by DOE under Grant No. DE-FG02-04ER46159 and Penn State nanofabrication lab.