Search for the chiral superconducting state in Sr2RuO4–Ru eutectic

Sr2RuO4 has become one of the most intensively studied transition metal oxides displaying unconventional superconductivity (Tc=1.5 K). It is known that its eutectic system Sr2RuO4–Ru shows interface superconductivity with an enhanced onset of ∼3 K. It is predicted that in the 3-K phase, a second transition to a chiral state occurs at a temperature between 1.5 and 3 K. The second transition is thought to be observable by ac-susceptibility measurements. We report the low-frequency ac-susceptibility of Sr2RuO4–Ru eutectic measured using a SQUID ac magnetometer.