Characterization of Sr2RuO4 Josephson junctions made of epitaxial films

We have studied the fundamental properties of weak-link ${\mathrm{Sr}}_{2}{\mathrm{RuO}}_{4}/{\mathrm{Sr}}_{2}{\mathrm{RuO}}_{4}$ Josephson junctions fabricated by making a narrow constriction on superconducting ${\mathrm{Sr}}_{2}{\mathrm{RuO}}_{4}$ films through laser micropatterning. The junctions show a typical overdamped behavior with much higher critical current density compared with those previously reported for bulk ${\mathrm{Sr}}_{2}{\mathrm{RuO}}_{4}/s$-wave-superconductor junctions. Observed magnetic-field and temperature dependencies of the Josephson critical current suggest that the chiral $p$ wave is unlikely for the superconducting symmetry, encouraging further theoretical calculations of the ${\mathrm{Sr}}_{2}{\mathrm{RuO}}_{4}/{\mathrm{Sr}}_{2}{\mathrm{RuO}}_{4}$-type junctions.