Multiple superconducting phases of Sr2RuO4 Original Research Article

A number of key experiments have provided strong evidence for spin–triplet symmetry in the superconductivity of Sr2RuO4 with However, there still remain important issues to be clarified before its superconducting state is fully understood. We will focus on two important issues, which appear to be intimately related to each other. First, we present evidence for multiple superconducting phases of Sr2RuO4 in magnetic fields precisely parallel to the RuO2 plane. Second, we show indications that the upper critical field Hc2 is strongly suppressed when the magnetic field is precisely parallel to the RuO2 plane. We discuss the relationship between these two phenomena, which are both characteristic of the parallel field configuration.