We measured the c-axis current-voltage (I-V) characteristics of Sr 2RuO4 and Ru-enriched Sr2RuO4 eutectic systems. Our results revealed that the 3-K phase in the Ru-Sr 2RuO4 eutectic system forms a complex Josephson network, which dominates the critical current of the system even at temperatures below bulk Tc. We also found that this Josephson network exhibits anomalous asymmetric features in I-V characteristics, such that the critical current density at positive current Jc+ differs from that at negative current Jc- by 5% at 0.3 K. This unusual behavior diminishes with increasing temperature or magnetic field. It disappears at temperatures above 2.3 K at zero field, or above 0.2 T at 0.3 K. We discuss these unusual behaviors in terms of a recent theory that argues a time reversal symmetry breaking transition in the 3-K phase.
|Original language||English (US)|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Jul 1 2004|
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics