Superconductivity in Sr2RuO4-Sr3Ru2O7 eutectic crystals

Superconducting behavior has been observed in the Sr(2)RuO(4)-Sr(3)Ru(2)O(7) eutectic system as grown by the flux-feeding floating-zone technique. A supercurrent flows across a single interface between Sr(2)RuO(4) and Sr(3)Ru(2)O(7) areas at distances that are far beyond those expected in a conventional proximity effect. The current-voltage characteristics within the Sr(3)Ru(2)O(7) macrodomain, as extracted from the eutectic, exhibit signatures of superconductivity in the bilayered Sr(3)Ru(2)O(7) region. Detailed microstructural, morphological and compositional analyses address issues on the concentration and the size of Sr(2)RuO(4) inclusions within the Sr(3)Ru(2)O(7) matrix. We speculate on the possibility of inhomogeneous superconductivity in the eutectic Sr(3)Ru(2)O(7) and exotic pairing induced by the Sr(2)RuO(4) inclusions.