Observation of Enhancement of the Superconducting Order Parameter in the Coexistent Antiferromagnetic State of SmRh4B4

Abstract

The first measurements of Josephson tunneling into both the paramagnetic and antiferromagnetic phases of Sm${\mathrm{Rh}}_4$ ${\mathrm{B}}_4$ are reported. The results show that the superconducting order parameter of Sm${\mathrm{Rh}}_4$ ${\mathrm{B}}_4$ is enhanced by the antiferromagnetic order occurring below the Neél temperature of about 0.87 K. On the basis of this observation, the applicability of various proposed theories of coexistent superconductivity and antiferromagnetism can be determined for Sm${\mathrm{Rh}}_4$ ${\mathrm{B}}_4$.