Abstract
The low-temperature magnetic behavior of the double-layered ruthenate SrRuO, as grown from a eutectic SrRuO-SrRuO system, was investigated via zero- and transverse-field muon-spin rotation. The gradual increase of the muon relaxation rate observed below 2.5 K, even in the absence of applied magnetic fields, indicates the occurrence of a spontaneous breaking of time-reversal symmetry. The onset of the latter at a temperature above 1.5 K, the of the single phase SrRuO, provides evidence about an unconventional superconducting state in the eutectic phase, which most likely takes place at the interface between the SrRuO and SrRuO domains, or even inside the SrRuO phase. We show that the superconducting state manifests a two-component behavior in the transverse-field response with change-over at about K and K. The comparison with zero-field SR data in the Ru-SrRuO eutectic system rules out the possibility of spurious effects due to embedded Ru islands.
- Received 9 August 2011
DOI:https://doi.org/10.1103/PhysRevB.85.134527
©2012 American Physical Society