<i>Josephson effect experiments probing the pairing symmetry of Sr₂RuO₄ </i>

Sr₂RuO₄ is an important unconventional superconductor predicted to be an odd-parity spin-triplet superconductor. Its order parameter (OP) symmetry has been the subject of intense scrutiny motivated by developments in the spin susceptibility measurements including NMR Knight shift and polarized neutron scattering that probe the spin part of the OP. While these new results do not exclude the odd parity, spin-triplet nature of the pairing state in this material, the phase-sensitive and spin counterflow half-quantum vortex measurements on Sr2RuO4 do exclude spin-singlet as the symmetry of the OP. Here we report measurements on Josephson effect devices of in-plane corner Josephson junctions prepared on both bulk crystals with two adjacent polished surfaces 90 degrees apart and thin crystals of a mesoscopic size obtained by mechanical exfoliation with two crystal edges of a known angle. Au0.5In0.5 or Al were used as the s-wave counter electrode for the junctions. The critical currents of these devices were measured as a function of the applied magnetic field. The results show the change in the phase of the OP under a rotation of 90 degrees or other angles. The implications of our results on the pairing symmetry in Sr₂RuO₄ will be discussed.