Observation of superconductivity in SrMnBi2 and Bi interface

• Observation of superconductivity at 5.7 K in SrMnBi2+Bi system.
• Superconductivity identified with an expanded Bi lattice at the Bi/SrMnBi2 interface based on SEM and XRD measurements.
• Vanishing of superconductivity upon grinding bulk samples.

We report observation of superconductivity at 5.7 K in the SrMnBi2+Bi system. SrMnBi2 single crystals and polycrystals were synthesized using stoichiometric mixtures of Sr, Mn and Bi. The resultant SrMnBi2 single crystals had pockets of rhombohedral Bi, precipitated at the surface of the crystals, as seen by SEM and XRD measurements. Resistivity and susceptibility measurements on bulk samples show superconductivity with transition temperature (TC) of 5.7 K. On grinding the bulk samples, superconductivity was seen to vanish together with the vanishing of the expanded Bi lattice peak. It is inferred that the observed superconductivity is associated with the interface in the SrMnBi2+Bi system.